The following books discuss various issues related to account and resource management, and are good resources for Red Hat Enterprise Linux system administrators.
The Security Guide; Red Hat, Inc — Provides an overview of the security-related aspects of user accounts, namely choosing strong passwords.
The Reference Guide; Red Hat, Inc — Contains detailed information on the users and groups present in Red Hat Enterprise Linux.
The System Administrators Guide; Red Hat, Inc — Includes a chapter on user and group configuration.
Linux Administration Handbook by Evi Nemeth, Garth Snyder, and Trent R. Hein; Prentice Hall — Provides a chapter on user account maintenance, a section on security as it relates to user account files, and a section on file attributes and permissions.