Blank-Edelman introduces this diversity of notation to motivate a far-reaching discussion of system internals, and shows how Perl is a natural choice for cross-platform administration. The Unix and Windows "slash" path separators--"/" and "\", respectively--are like crossed swords, where the Mac OS uses the less- generally-known colon (":"). In lesser hands, this treatment still would have been about LAN backups, but Blank-Edelman's familiarity with network imperatives drives the synthesis.

As the topics move beyond file systems, user accounts, and process control, the tripartite division in the discussion breaks down. Treatments of TCP/IP and e-mail feature discussions of NIS, WINS, DNS, and nslookup. The chapters on directory services and SQL database management--while apparently digressive--are inserted tactically to enable elegant approaches to the more mundane administrative tasks of sending and receiving e-mail and managing log files to maximize their utility. Blank-Edelman's keen pragmatism shines in the chapter on security in which noticing intrusion earlier instead of later draws on many of the skills that are developed throughout the book. Notably, each chapter ends with a recapitulation of Perl modules that were referenced in the preceding text.

The eclectic tutorial appendices--an old revision-control system (RCS), the extensible markup language (XML), the database language (SQL), and two undermotivated and esoteric protocols (LDAP and SNMP)--are so brief as to function more as a Perl-free zone for shop talk than as valuable précis for their respective subjects.

Delightfully, this is one of Perl's and O'Reilly's best-written books. Blank-Edelman's wit buoys the argument without descending into the all-too-common parlance of sappy testimonials, hollow confessions, or the burdensome ornamentation of inside jokes and puns. --Peter Leopold