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 * [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)