Far too many errors to be useful. I there was a rating below one star this book would get it! I can only repeat this comment: "On average, there is one error per 2 pages of this book! Really. It's unbelievable that McGraw Hill would let something like it out. It's not just the explanatory text, but the sample questions are full of errors, too. " So you must know LotusScript pretty well to be able to identify the errors and understand that the book is wrong and not you. This is not of any use if you are using this book to prepare for the exam. I have written to McGraw Hill but got no response so far, I believe they owe anyone who has purchased this book an update. There is no errata for this on the web site (and the book has been out for 7 months).