A jaded software developer, having seen too many insubstantial "advance" books rushed to press just so they can be the only books available on their topic for a while, might be suspicious of this book. Such suspicion is not borne out by the contents of Perl 6 Essentials, which are valuable. Though thin, this book is dense with information and well worth its modest cover price. The authors clearly explain what's new (so far) in Perl 6, and do an excellent job of explaining the new Parrot virtual machine architecture. There's extensive coverage of Parrot assembly language (PASM), more than enough for you to do some significant exploratory programming with it. The authors have a good sense of what Perl developers want to know about their future working environment, and satisfy that demand. --David Wall

Topics covered: The state of the Perl 6 development effort through Apocalypse 6 (a development milestone) and the Parrot virtual machine through version 0.0.10. The most valuable coverage is of Parrot and its assembly language (PASM). Changes in Perl features and syntax get lots of attention, as well.