At over 1000 pages, the book may look intimidating. However, this book is really a collection of independent articles, each just one to two pages long, that talk about a specific topic or solve a specific problem. The book is not meant to be read in order. Instead, look up something when you need to, or just flip to a random page and learn something new about UNIX.
For example, I learned the following two tips just from browsing:
A CD-ROM is included with all the shell scripts presented in the text. The binary executables on the CD-ROM ran on our Series 705 workstation immediately with no recompilation required. Very handy.