This book has some good info on MaxScript writing and is definately a better learning resource than 3DSMax's on-line reference. However, the book's effectiveness is marred somewhat by sloppy execution.
I've found numerous syntax errors and ambiguous line breaks while working through the lessons (i.e. code that must be on one line is listed as two lines without any sort of continuation mark shown. Extra commas when there should be none, etc.). And while most of these problems can be worked through by referencing the Maxscript help file, it forces the reader play detective when the code they've copied verbatim from the book generates unexpected errors.
In addition, the text is far too reliant on the (often poorly formatted and uncommented) files contained in the attached CD-ROM. Too often, the reader is forced to open a file to see the syntax referenced in the lesson because it's not fully explained in the book itself. This can be highly annoying if you're reading at multiple locations (work, home) and have forgotten to take the CD with you.