I have to say that this book disappointed me, given that the O'Reilly JavaScript book was pretty good. It is true that this book does not 'teach' the language, but I thought that the explanations could have been clearer and more thorough. The examples usually consisted of foo this and goo that - which do not relate to any real world circumstance and therefore made them somewhat confusing (and rather dull). Quite often it was difficult to see how the example related to the topic being described! And examples were often omitted following some subtle syntax explanation - for example, you can specify a number to be Long using the L suffix... a one line example would make this very clear - but no example exists.
The command syntax specifications use some XML type mark-up symbols, which are different to the usual notation: An example (variable declaration): type [variable [ = expression ] ? ] + ; usual notation would imply that the variable is Optional! - here it allows the + sign to indicate 'one-or-more' occurrences.
Cross references in the book, for example: (see "decimal type" section in chapter 2) would be slightly better if they included a page reference - given that section 2 is 70 pages it takes a bit of page flipping to find the place. Also, like many languages, you have to use elements of the language in early parts of the book before you get to the place where they are described and defined. Some explanation or cross referencing would be helpful here too - else like the compiler you would need to read the book twice to understand it. But it's just too dull to read twice!
I do hope they produce a more complete and interesting version 2 edition after .Net becomes available.