One False Note, the second book in the 39 clues series, by Gordon Korman was a very well-written book. Again I thought the characters were cracking jokes too often to be believable, but besides that, the plot was pretty well-built. I especially liked the fact that you couldn't always see what was going to happen; there were many unexpected twists and turns. The ideas were really great and I would suggest this book to my friends and anyone else who had read the first book.
Tompkins County Public Library