The Imposter’s Handbook
A good look at all the skills you should know but don’t if you’re developing without a CS degree. My degree was in Political Science (I was going to go to law school), and I’m a self-taught programmer. This book covered a lot of things I sort of knew but had never really studied (especially data structures).
The book is a little uneven at times – it takes a weirdly detailed detour into how to write a Makefile script at the end, for example – but is really a great resource for “imposters” who think everyone knows more than they do.