Some of the subjects it treats are low-level enough (and of Unix-ish heritage) that their treatment is probably not irrelevant today. The performance considerat

Some of the subjects it treats are low-level enough (and of Unix-ish heritage) that their treatment is probably not irrelevant today. The performance considerations of threads and processes are probably out of date, but their API (sections 3 and 4) is largely still the same. Same for shared memory and other IPC mechanisms described in section 5. The API re. section 7 still applies -- /proc has expanded considerably since 2001, but it's still used in the same manner. Chapter 8 is probably more out of date than others, but you can still follow it. Stuff in 9 is probably not used much anymore, an #10, while adequate, would probably be considered incomplete today. I'd say it's still useful to someone who comes to Linux from other platforms, or to people who are already using Linux but aren't familiar with systems programming under it. Edit: although, as someone else pointed out, APUE is probably a better choice (and was a better choice back in 2001, too).