Jeff Duntemann's book on Turbo Pascal is still one of my favorite texts of all time. He combined his enthusiasm for the subject with a deft hand at explaining concepts intuitively.

And of course, there was Peter Norton's Guide to the IBM PC. The bible, back then.

Not only that, but Turbo Pascal was very efficient as a linker too, linking only library code that was actually used in the program, as opposed to Turbo C/C++ that would link the entire library. As a result, "Hello, World" was ~2KB for TP vs. ~15KB for TC. I may not remember the sizes correctly, but the difference was dramatic. Of course, for bigger programs the difference was a bit smaller. And it was fast!