Turbo Pascal was my first real programming language (after BASIC and a bit of 8086 assembly) in my pre-teen years, and I read the manual very thoroughly. It was fascinating to learn, even though much of it was over my head.

I remember sitting at the living room table on many evenings, studying a stack of printed out source code. My task was to contribute to translating a bulletin board system called WWIV.

https://en.wikipedia.org/wiki/WWIV

I went on to study Turbo C, which came with a wonderfully informative manual also. That experience formed the foundation of my programming in the next decades (2~3).

And Jeff Duntemann's outstanding "Complete Turbo Pascal".