Yes, it's useful as an aid to understanding the DVD authoring process. I would suggest starting with another book, however, called "DVD Demystified" by Jim Taylor. Ralph's book then made more sense, to me at least.
It has no direct bearing on VV, in that it deals with authoring while VV deals with NLE. The "assets" that are used to build DVDs are MPEG2 files. Some authoring programs prefer Program Streams (video and audio multiplexed together), and other programs prefer Elementary Streams (video and audio streams brought in separately). To build those MPEG2 streams you either use the MainConcept codec built into VV3, or you take the avi files created by Vegas over to a standalone codec such as TMPGEnc, Ligos, or CinemaCraft.
The only potential problem with both books is that the material can get stale in this quickly-changing arena. Ralph's book in particular contains lots of information about company names and products, and much of that section needs updating.