About Programming in assembly language and especially how to boot your programs. This book is full of interesting things about computers that are chosen to be useful for BOOTABLE assembly language. Including, how to switch a computer into its 64 bit mode, and then from 64 bit mode back again to 16 bit mode. And how to find the high resolution screen memory. And how to draw alphabetical letters when in a graphics screen mode. And how to start learning how to program the USB controller. (Of course bootable programming is when your program runs on its own, and there is no operating system. When you add more and more to your bootable programs they can gradually develop to become a small operating system of their own.)