i bought this book with ambitions of teaching myself linux internals or being able to read the print version of the source for reference. if find myself frequenting online groups and threads for more and better answers than the book provides. also the kernel is older than the current 2.4x. in particular i was looking for CIFS vfs stuff which wasn't in this at all (but is in 2.4x).so two stars because i haven't been able to use it much. others may find it more relevant in their "core" areas.