This book teaches assembly language for x86 processors and the GNU/Linux
operating system.
Skimming through the book and reading a blurb here and there, the book IS about assembly and it is based totally on compiling through the Linux kernel. The book starts out and goes through describing the basics of how a kernel, window manager, and application work in sync and then it goes on and introduces assembly and teaches the fundamentals such as variables and basic syntax and eventually leads into how to code your very first program using the lanaguage...

So if you want assembly, read away.