Here is an excellent collection of 45 free books in PDF format which I found here — "Programming Notes for Professionals" books.
The PDFs contain this on one of their very first pages:
Please feel free to share this PDF with anyone for free
This ${insert title here} Notes for Professionals book is compiled from Stack
Overflow Documentation, the content is written by the beautiful people at Stack
Overflow. Text content is released under Creative Commons BY-SA, see credits at
the end of this book whom contributed to the various chapters. Images may be
copyright of their respective owners unless otherwise specified.
Because of the range of software development related topics covered, I thought this might be of interest to a large fraction of people on SN.
(Score: 0) by Anonymous Coward on Monday January 22 2018, @04:57PM
Yep. That's the main problem with Stack Overflow. I do sometimes consult SO for solutions to notty computer programming problems. Many times there is at least one person who has a good answer to my problem, but there are several that are talking out of their asses. It's a game of sifting to separate the wheat from the chaff. Remember, you get what you pay for.