[Javascript] Good Javascript book

[Andrew Dunn]

Hi,
   I would like to purchase a really good Javascipt book. At the moment the
only book I have on Javascript is SAMS Javascript Unleashed. This book is
good, but I feel it is out of date as it lists things like Browsers
detection techniques as an essential programming technique. What I'm after
is a "definitive resource". I suppose their isn't really one out their but
If anyone could suggest any good books pleas

Thanks.