Richard Feynman's Lectures on Physics are timeless: their main strength is in demonstrating how to reason about physics. twitter 
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This New Millennium Edition ushers in a new era for The Feynman Lectures on Physics with the text and equations expressed in the LaTeX electronic typesetting language, and all figures redone using modern drawing software.
Volume I
mainly mechanics, radiation, and heat. toc
Volume II
mainly electromagnetism and matter. toc
Volume III
quantum mechanics. toc
The Feynman Lectures on Physics is perhaps the most popular physics book ever written. More than 1.5 million English-language copies have been sold; probably even more copies have been sold in a dozen foreign-language editions. A 2013 review in Nature described the book as having "simplicity, beauty, unity ... presented with enthusiasm and insight". wikipedia
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Volume II would have been covered in my "fields" class in college. My professor said, if you like this stuff, get Feynman. Five decades later I have this page to admire.