When I was an undergrad and graduate EE student, the &quot;go to&quot; book to help with electromagnetics was <i>Div, Grad, Curl, and all that</i> (<a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;Div-Grad-Curl-All-That&#x2F;dp&#x2F;0393925161" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;Div-Grad-Curl-All-That&#x2F;dp&#x2F;0393925161</a>). Back in my era it was the 1st edition of the book, not the 4th.<p>I see another book with good recommendations, <i>A Student&#x27;s Guide to Maxwell&#x27;s Equations</i> (<a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;Students-Guide-Maxwells-Equations&#x2F;dp&#x2F;0521701473" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;Students-Guide-Maxwells-Equations&#x2F;dp&#x2F;0...</a>) but I have not read that one.<p>Div, Grad, Curl helped a bit, but what really made it click for me was an excellent professor some other EE math-class-in-disguise that explained those vector calc operations in terms of divergence (source density) and flux (change in time&#x2F;space).<p>As far as understanding the linked paper, I can&#x27;t follow the proof either. Equations 1-4 I&#x27;ve never seen, 5-8 are Maxwell&#x27;s Equations which are familiar but we wrote them with different notation, 9-18 are again equations I&#x27;ve never seen. The meat of the proof in 19-21 is built on 14 mystery equations and 4 that I recognize.<p>As a former EE I guess we didn&#x27;t prove equations as much as take their existence as given and then figured out what that implied for the real world. ;) Other posters aroberge and wraithm have mentioned also needing QM from physics to follow the proof, which must be where the other equations are from!