This free programming book gives readers practical, in-depth methods for reverse engineering software, starting with a fundamental primer on the subject that covers computer internals, operating systems, and assembly language. The book also discusses the numerous uses of reverse...

In 2014–2018, the title of the book was "Reverse Engineering for Beginners," but I've always had the sneaking suspicion that that made his audience too limited. 

For those new to reverse engineering who want to learn how to understand x86 (which makes up nearly all executable software in the world) and ARM code produced by C/C++ compilers, this book provides a primer, delving into "disassembly"-code-level...