Operating systems: design and implementation by Andrew S. Tanenbaum.

It talks alot about Minix:

WHAT IS MINIX 2.0
MINIX is a free UNIX clone that is available with all the source code. Due to its small size, microkernel-based design, and ample documentation, it is well suited to people who want to run a UNIX-like system on their personal computer and learn about how such systems work inside. It is quite feasible for a person unfamiliar with operating system internals to understand nearly the entire system with a few months of use and study.
MINIX BOOK
MINIX has been designed as a teaching system. It is easy to learn and maintain. A book describing operating systems in general and how MINIX works in particular is available. It can be used as a textbook or for independent study. The bibliographic information is:
Title: Operating Systems: Design and Implementation, 2/e
Authors: Andrew S. Tanenbaum, Albert S. Woodhull
Publisher: Prentice-Hall