It's a big book, so have only skimmed through, but it seems very good, well researched and useful.
Most of the book is applicable regardless of what the OS is, as it seems to teach you the fundamentals of reading ASM and recognising code patterns in binaries. It even has a full chapter in OS-specific reversing.
It certainly worth a time I've spent to read it, even if I'm not a beginner. There are parts, that will be useful for a reverse engineer of every level.
Most of the book is applicable regardless of what the OS is, as it seems to teach you the fundamentals of reading ASM and recognising code patterns in binaries. It even has a full chapter in OS-specific reversing.