**Note**: In order of [Library of Congress Classification](http://www.loc.gov/catdir/cpso/lcco/)


# [(B)](https://www.loc.gov/aba/cataloging/classification/lcco/lcco_b.pdf)  PHILOSOPHY, PSYCHOLOGY, RELIGION

## (BF) Psychology

* [Computational Cognitive Neuroscience](https://github.com/CompCogNeuro/ed4) - Randall C. O’Reilly Yuko Munakata Michael J. Frank Thomas E. Hazy
* [ePsych](https://epsych.msstate.edu) - Gary L. Bradshaw
* [Instances of Cognition](https://www.crumplab.com/cognition/textbook) - Matthew J. Crump
* [Neural Networks - A Systematic Introduction](http://page.mi.fu-berlin.de/rojas/neural/) - Raul Rojas
* [Neuronal Dynamics: From single neurons to networks and models of cognition](https://neuronaldynamics.epfl.ch) - Wulfram Gerstner, Werner M. Kistler, Richard Naud and Liam Paninski
* [Neuroscience](https://www.bna.org.uk/static/uploads/resources/BNA_English.pdf) - British Neuroscience Association European Dana Alliance for the Brain (PDF)
* [Neuroscience Online](https://nba.uth.tmc.edu/neuroscience/) - John H. Byrne
* [Probabilistic Models of Cognition](https://probmods.org) - Noah D. Goodman et al.
* [Psychology: An Introduction](https://www.psywww.com/intropsych) - Russell A. Dewey
* [Spiking Neuron Models Single Neurons, Populations, Plasticity](https://lcnwww.epfl.ch/gerstner/SPNM/) - Wulfram Gerstner and Werner M. Kistler
* [The Brain Facts Book](https://www.brainfacts.org/The-Brain-Facts-Book)
* [The Psychology of Learning](https://www.psychologyoflearning.be) - Jan De Houwer and Sean Hughes


# [(Q)](https://www.loc.gov/aba/cataloging/classification/lcco/lcco_q.pdf) Science (General)

## (QA) Mathematics

* [A First Course in Linear Algebra](http://linear.ups.edu) - Robert A. Beezer
* [A Pragmatic Introduction to Signal Processing with applications in scientific measurement](https://terpconnect.umd.edu/~toh/spectrum/TOC.html) - Tom O'Haver (online)
* [Advanced Algebra](http://www.math.stonybrook.edu/~aknapp/download/a2-alg-inside.pdf) - Anthony W. Knapp (PDF)
* [Advanced Calculus](http://www.oercommons.org/courses/advanced-calculus/view) - Lynn H. Loomis and Shlomost Ernberg (PDF)
* [An Introduction to Mathematical Reasoning](http://www.maths.manchester.ac.uk/~nige/IMRpartI.pdf) - Peter J. Eccles (PDF)
* [An Introduction to the Theory of Numbers](http://www.trillia.com/moser-number.html) - Leo Moser (PDF)
* [Basic Algebra](http://www.math.stonybrook.edu/~aknapp/download/b2-alg-inside.pdf) - Anthony W. Knapp (PDF)
* [Basic Concepts of Mathematics](http://www.trillia.com/dA/zakon-basic-a4-one.pdf) - Elias Zakon (PDF)
* [Basics of Algebra, Topology, and Differential Calculus](http://www.cis.upenn.edu/~jean/math-basics.pdf) (PDF)
* [Book Of Proof (2013)](http://www.people.vcu.edu/~rhammack/BookOfProof) - Richard Hammack
* [Calculus](https://ocw.mit.edu/ans7870/resources/Strang/Edited/Calculus/Calculus.pdf) - Gilbert Strang (PDF)
* [Calculus Better Explained](https://betterexplained.com/calculus/) - Kalid Azad (online)
* [Calculus Made Easy](http://www.gutenberg.org/ebooks/33283) - Silvanus P. Thompson (PDF)
* [CLP-1 Differential Calculus textbook](http://www.math.ubc.ca/~CLP/CLP1/clp_1_dc_text.pdf) - Joel Feldman, Andrew Rechnitzer, Elyse Yeager (PDF)
* [College Geometry](http://math.unideb.hu/media/vincze-csaba/collegegeom-main-1.pdf) - Csaba Vincze and László Kozma (PDF)
* [Computational Geometry](http://web.mit.edu/hyperbook/Patrikalakis-Maekawa-Cho/)
* [Elementary Algebra (2011)](http://www.mathhands.com/046) - Francisco Javier Márquez
* [Elementary Differential Equations](http://ramanujan.math.trinity.edu/wtrench/texts/TRENCH_DIFF_EQNS_I.PDF) - William F. Trench (PDF)
* [Encyclopedia of Mathematics](https://www.encyclopediaofmath.org/index.php/Special:AllPages) - Springer
* [Graph Theory](http://compalg.inf.elte.hu/~tony/Oktatas/TDK/FINAL/) - Iványi Antal Miklós
* [How We Got From There to Here: A Store of Real Analysis](https://textbooks.opensuny.org/how-we-got-from-there-to-here-a-story-of-real-analysis/) - Robert Rogers and Eugene C. Boman (HTML, PDF)
* [Introduction to Probability](http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html) - Charles M. Grinstead and J. Laurie Snell
* [Introduction to Probability and Statistics Spring 2014](http://ocw.mit.edu/courses/mathematics/18-05-introduction-to-probability-and-statistics-spring-2014/) -  Jeremy Orloff, Jonathan Bloom
* [Introduction to Proofs](http://joshua.smcvt.edu/proofs/) - Jim Hefferon
* [Introduction to Statistical Thought](http://people.math.umass.edu/~lavine/Book/book.html) - Michael Lavine
* [Lecture Notes of Linear Algebra](http://home.iitk.ac.in/~psraj/mth102/lecture_notes.html) - Dr. P. Shunmugaraj, IIT Kanpur (PDF)
* [Linear Algebra](http://home.iitk.ac.in/~arlal/book/nptel/pdf/booklinear.html) - Dr. Arbind K Lal, IIT Kanpur (PDF)
* [Linear Algebra](https://www.math.ucdavis.edu/~linear/linear-guest.pdf) - David Cherney, Tom Denton, Rohit Thomas and Andrew Waldron (PDF)
* [Linear Algebra by Jim Hefferon](http://joshua.smcvt.edu/linearalgebra) - Jim Hefferon
* [Linear Algebra Notes](http://scipp.ucsc.edu/~haber/ph116A/new_linearalgebra.pdf) - David A. Santos (PDF)
* [Mathematical Logic - an Introduction](http://www.ii.uib.no/~michal/und/i227/book/book.pdf) (PDF)
* [Mathematics For Computer Science (2017)](https://courses.csail.mit.edu/6.042/spring17/mcs.pdf) - Eric Lehman et al. (PDF)
* [Mathematics For Machine Learning](https://mml-book.github.io/book/mml-book.pdf) - Marc Peter Deisenroth, A. Aldo Faisal and Cheng Soon Ong (PDF)
* [Mathematics for Physics](http://www.goldbart.gatech.edu/PostScript/MS_PG_book/bookmaster.pdf) - Michael Stone and Paul Goldbart (PDF)
* [Mathematics Formulary](https://johanw.home.xs4all.nl/math.pdf) - J.C.A. Wevers (PDF)
* [Modern Elementary Geometry](https://digital.lib.washington.edu/researchworks/bitstream/handle/1773/15592/Lectures_of_polygons_%20BG_1997.pdf?sequence=1) - B. Grünbaum (PDF)
* [Number Theory](https://github.com/holdenlee/number-theory) - Holden Lee MIT
* [OpenIntro Statistics](https://www.openintro.org/stat/textbook.php)
* [OpenStax - Mathematics](https://openstax.org/subjects/math) - OpenStax (PDF)
* [Ordinary Differential Equations](https://en.wikibooks.org/wiki/Ordinary_Differential_Equations) - Wikibooks
* [Probability and Statistics Cookbook](http://statistics.zone)
* [Probability and Statistics EBook](http://wiki.stat.ucla.edu/socr/index.php/Probability_and_statistics_EBook)
* [Stacks Project](http://stacks.math.columbia.edu)
* [Statistics Done Wrong](http://www.statisticsdonewrong.com) - Alex Reinhart
* [The Handbook of Essential Mathematics ](https://florida.theorangegrove.org/og/file/3a8c652c-11d0-e967-95fb-b5bbae2586d6/1/math_handbook.pdf) - John C. Sparks (PDF)
* [Trigonometry Lecture Notes And Exercises](http://pages.uoregon.edu/raies/Teaching%20Documents/Math%20112%20-%20Spring%202014/Lecture_Notes.pdf) - D. Raies (PDF)
* [Understanding Basic Calculus](http://www.math.nagoya-u.ac.jp/~richard/teaching/f2015/BasicCalculus.pdf) - S.K. Chung (PDF)


## (QB) Astronomy

* [A Short History of Astronomy (1898)](https://ia601408.us.archive.org/16/items/shorthistoryofas025511mbp/shorthistoryofas025511mbp.pdf) - Arthur Berry (PDF)
* [Archaeology, Anthropology, and Interstellar Communication (2014)](https://unglue.it/work/139785/) - Douglas A. Vakoch
* [Astronomy (1877)](https://unglue.it/work/81942/) - Sir Robert Stawell Ball 
* [Astronomy (1915)](https://unglue.it/work/81943/) - Harold Jacoby
* [Astronomy (OpenStax)](https://openstax.org/details/books/astronomy) - Andrew Fraknoi et al. (PDF)
* [Elements of astronomy (1836)](https://unglue.it/work/81958/) - John Hubbard Wilkins
* [Hubble 25: A Quarter-Century of Discovery with the Hubble Space Telescope (2015)](https://unglue.it/work/145858/) - Dylan Steele


## (QC) Physics

* [A Text Book for High School Students Studying Physics](http://ftp.igh.cnrs.fr/pub/nongnu//fhsst/Physics_Grade_10-12.pdf) - FHSST Authors (PDF)
* [An introduction to Physics](http://eacpe.org/content/uploads/2014/01/PHYSICS-101.pdf) - Pervez Hoodbhoy (PDF)
* [Atomic and Molecular Physics - Lecture Notes](http://www.yorku.ca/tomk/PHYS4011-W13.pdf) - Tom Kirchner (PDF)
* [Chaos: Classical and Quantum](http://chaosbook.org) - Predrag Cvitanović, Roberto Artuso, Ronnie Mainieri et al.
* [Classical Dynamics](http://www.damtp.cam.ac.uk/user/tong/dynamics/clas.pdf) - David Tong (PDF)
* [Classical Mechanics](http://www.physics.rutgers.edu/ugrad/494/bookr03D.pdf) - Joel A. Shapiro (PDF)
* [Conceptual Physics](https://www.lightandmatter.com/cp) - Benjamin Crowell (PDF)
* [Dynamics and Relativity](http://www.damtp.cam.ac.uk/user/tong/relativity/dynrel.pdf) - David Tong (PDF)
* [Fields and Circuits](https://www.lightandmatter.com/fac) - Benjamin Crowell (PDF)
* [Fundamental Physics for Level 0 - Teaching Guide](https://web.archive.org/web/20170701234819/https://oup.com.pk/media/teaching-guides/Fundamental%20Biology%20Physics%20Chemistry/Fundamental%20Physics%20for%20O%20Level%20Teaching%20Guide.pdf) - Ian Collins (PDF)
* [Fusion Physics](https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1562_web.pdf) - (PDF)
* [General Relativity](https://www.lightandmatter.com/genrel) - Benjamin Crowell (PDF)
* [GRE Physics Test Practice Book](https://www.ets.org/s/gre/pdf/practice_book_physics.pdf) - (PDF)
* [Introduction to General Relativity](http://www.staff.science.uu.nl/~hooft101/lectures/genrel_2013.pdf) - Gerard ’t Hooft (PDF)
* [Introductory Physics I - Elementary Mechanics](https://webhome.phy.duke.edu/~rgb/Class/intro_physics_1/intro_physics_1.pdf) - R.G. Brown (PDF)
* [Lecture Notes in Quantum Mechanics](https://physics.bgu.ac.il/~dcohen/ARCHIVE/qmc.pdf) - Doron Cohen (PDF)
* [Lecture Notes on General Relativity](https://home.uni-leipzig.de/~tet/wp-content/uploads/2014/04/GR2015_0903.pdf) - Hollands and Sanders (PDF)
* [Lecture Notes on Thermodynamics](http://www.crectirupati.com/sites/default/files/lecture_notes/TD-lecture%20notes.pdf) - Munirathnam (PDF)
* [Light and Matter](https://www.lightandmatter.com/lm) - Benjamin Crowell (PDF)
* [Mathematical Methods in Physics - Course Notes](https://www.pa.ucla.edu/faculty-websites/dhoker-lecture-notes/graduate-courses/231A-lecture-notes-15.pdf) - Eric D’Hoker (PDF)
* [Modern Physics](https://www.lightandmatter.com/mod) - Benjamin Crowell (PDF)
* [Motion Mountain Physics](http://www.motionmountain.net) - Christoph Schiller
* [Physics Before and After Einstein](http://www.dmi.unipg.it/mamone/pubb/PBAE.pdf) - Marco Mamone Capria (PDF)
* [Physics Test Practice Book](https://www.physics.ohio-state.edu/undergrad/greStuff/exam_GR9677.pdf) - (PDF)
* [Problems in Introductory Physics](http://www.lightandmatter.com/problems/problems.pdf) - B. Crowell and B. Shotwell (PDF)
* [Radiation and particle detectors (2011)](https://www.asc.ohio-state.edu/honscheid.1/s12-780/references/turku_lecturenotes.pdf) - Edwin Kukk (PDF)
* [Radiaton Physics for Personnel and Environmental Protection (2007)](https://www-esh.fnal.gov/TM1834_PDF_Files/TM_1834_Revision_9B.pdf) - J. Donald Cossairt (PDF)
* [Relativity for Poets](https://www.lightandmatter.com/poets) - Benjamin Crowell (PDF)
* [Special Relativity](https://www.lightandmatter.com/sr) - Benjamin Crowell (PDF)
* [Statistical Physics](http://www.damtp.cam.ac.uk/user/tong/statphys/sp.pdf) - David Tong (PDF)
* [Structure and Interpretation of Classical Mechancics](https://mitpress.mit.edu/sites/default/files/titles/content/sicm_edition_2/book.html) - Gerald Jay Sussman and Jack Wisdom
* [The Feynman Lectures on Physics](http://feynmanlectures.caltech.edu) - Richard P. Feynmann
* [The Physics Hypertextbook](https://physics.info) - Glenn Elert
* [University Physics, Volume 1](https://openstax.org/details/books/university-physics-volume-1) - William Moebs, Samuel J. Ling, Jeff Sanny et al. (PDF)
* [University Physics, Volume 2](https://openstax.org/details/books/university-physics-volume-2) - William Moebs, Samuel J. Ling, Jeff Sanny et al. (PDF)
* [University Physics, Volume 3](https://openstax.org/details/books/university-physics-volume-3) - William Moebs, Samuel J. Ling, Jeff Sanny et al. (PDF)


## (QD) Chemistry

* [A Dictionary of Chemistry (1777)](https://unglue.it/work/140195/) - Pierre Joseph Macquer and James Keir
* [Biochemistry from a phenomenological point of view](http://www.louisbolk.org/downloads/1282.pdf) - Christa van Tellingen (PDF)
* [Biochemistry Practice Book](http://www.ets.org/s/gre/pdf/practice_book_biochem.pdf) - (PDF)
* [Chemistry 2e](https://openstax.org/details/books/chemistry-2e) - Paul Flowers, Klaus Theopold, Richard Langley et al. (PDF)
* [Chemistry: Atoms First 2e](https://openstax.org/details/books/chemistry-atoms-first-2e) - Paul Flowers, Edward J. Neth, William R. Robinson et al. (PDF) 
* [CK-12 Chemistry - Second Edition (2011)](https://unglue.it/work/140345/) - Sharon Bewick et al.
* [Electrochemistry](https://unglue.it/work/488281/) - Mohammed A. A. Khalid
* [From Vitamins to Baked Goods: Real Applications of Organic Chemistry (2012)](https://unglue.it/work/145870/) - Kieran Gallagher and Lizhi Fan
* [Green Chemistry](https://unglue.it/work/488195/) - Mazaahir Kidwai, Neeraj Kumar Mishra
* [Introduction to Chemistry](https://unglue.it/download_ebook/54777/) - Tracy Poulsen (PDF)
* [The Story of Alchemy and the Beginnings of Chemistry (1902)](https://www.gutenberg.org/ebooks/14218) - M. M. Pattison Muir


## (QE) Geology

* [An Introduction to Geology](http://opengeology.org/textbook/) - Chris Johnson, Matt Affolter, Paul Inkenbrandt, Cam Mosher
* [Physical Geology](https://opentextbc.ca/geology/open/download?type=pdf) - Steven Earle (PDF)


## (QH) Natural history

* [Selected Records of Reptiles and Amphibians from Kansas (1946)](https://www.gutenberg.org/ebooks/34554) - John Breukelman and Hobart Smith


## (QK) Botany

* [Beginners' Botany (1921)](http://ia801405.us.archive.org/5/items/beginners21west00bailuoft/beginners21west00bailuoft.pdf) - L.H. Bailey (PDF)


## (QL) Zoology

* [Mammals of the Southwest Mountains and Mesas (1961)](https://www.gutenberg.org/ebooks/50822) - George Olin


## (QM) Human anatomy

* [The Anatomy of the Human Peritoneum and Abdominal Cavity (1903)](https://www.gutenberg.org/ebooks/43350) - George S. Huntington 


## (QP) Physiology

* [The Glands Regulating Personality (1922)](https://www.gutenberg.org/ebooks/10266) - Louis Berman


## (QR) Microbiology

* [Microbiology](https://openstax.org/details/books/microbiology) - Nina Parker, Mark Schneegurt, Philip Lister et al. (PDF)


# [(R)](http://www.loc.gov/aba/cataloging/classification/lcco/lcco_r.pdf) Medicine 

## (RT) Nursing

* [Nursing as Caring: A Model for Transforming Practice (1993)](https://www.gutenberg.org/ebooks/42988) - Boykin and Schoenhofer


# [(T)](http://www.loc.gov/aba/cataloging/classification/lcco/lcco_t.pdf) Technology

## (TJ) Mechanical engineering and machinery (includes Energy Conservation)

* [Climate Change and the Oil Industry (2003)](https://unglue.it/work/138838/) - Jon Birger Skjaerseth and Tora Skodvin
* [Our Car as Power Plant (2014)](https://unglue.it/work/129373/) - Ad van Wijk and Leendert Verhoef 
* [Sustainable Energy - without the hot air (2009)](https://unglue.it/work/140777/) - David J. C. MacKay
* [Understanding the Global Energy Crisis (2014)](https://unglue.it/work/136212/) - Eugene D. Coyle and Richard A. Simmons


## (TP) Chemical Technology

* [Acids, Alkalis and Salts (1919)](https://www.gutenberg.org/ebooks/50552) - George Henry Joseph Adlam
* [Creative Chemistry: Descriptive of Recent Achievements in the Chemical (1919)](https://www.gutenberg.org/ebooks/17149) - Edwin E. Slossan
* [Pyrotechnics: The History and Art of Firework Making (1918)](https://www.gutenberg.org/cache/epub/64922/pg64922-images.html) - Alan St. H. Brock