art of unix programming

I recently read eric s. raymond's book, the art of unix programming and it is great. This is not a how-to book, but rather it explains the underlying theory of how the unix environment supports the development of programs and applications. In many ways it is an extention of the book the linux and unix philosophy that I discribed in an earlier posting. Raymond's book gives a lot of insights into how and why the unix environment works so well. This book is worth reading for the understanding it gives the reader about unix, c, and program development