UNIX Concepts and Applications, 4th Edition was written bearing in mind that although this book deals with a specific operating system, it should help the user understand operating systems in general. The content-organization of the book is such that it addresses two levels of users. The first part of the book caters to the beginners while the second part caters to the advanced UNIX users.

Sumitabha Das has a degree in electronics engineering from Calcutta University (1977). He picked up his interest in UNIX when working at the Ministry of Defence. Today, he teaches UNIX and Systems Programming. He is ably supported by his wife and daugher.