Ruby in a Nutshell - still worthwhile?

[Jeff Cohen]

I'm looking for a quick reference guide to Ruby. I have the PickAxe
already, which is great for learning Ruby, but now I'm looking for
something more reference-like and smaller

The O'Reilly "in a nutshell" book is from 2001 and covers only up to
1.6. I imagine they're waiting for 2.0 before the do another book.

Is the book still worth getting? Is there a different
quick-reference/quick-explanation guide that people recommend?

Thanks
Jeff