While I can sympathise with some of the 2* reviewers, I am reluctant to rate this anything less than 5*. While I myself did (and still do) struggle with this book, it's fair to say that it really does its best to get you from novice TO professional in its 480 pages.
I won't lie and pretend this is easy-going. It's not. But I think as a beginner that if you're willing to go with the flow and accept that not everything is going to make sense at first, and if you're prepared to write your own scripts (and accept they're not going to be as good as Heilmann's right away) you'll have here an invaluable resource. Not only does he cover a bunch of relevant examples (e.g. drop down menus, layer ads, form validation), but he does this well. When I go and write my own scripts, I never feel like i'm coming back to this book to 'look how it's done', rather it's that i'm coming back to 'see a better approach'.
N.B. all code examples are available online for download to accompany this book. This is another handy facet.