It's a nice book. similar format to his "Programming with RISC OS Toolkit. written using TechWriter on an Iyonix. The introduction, explaining what UnixLib is, is followed by a fascinating chapter on the History of UnixLib from 1989 to the present day.
Then it gets down and dirty with detailed information on how to use it with separate chapters on Files, Directories, Sockets, Name Resolution, Processes, Threads, Globbing, Regular Expressions, CLI and SysLog.
Even for a non-coder the book has a fair amount of interest for example the explanations of Globbing and Regular Expression.
(for Graham - there is a typo on page 9 start of penultimate paragraph