I think you chose a good book for learning Ruby. And THE book for  
learning Rails. I've got both books.
But you need the actually pickaxe book, Programming Ruby, as a  
reference manual. It is not the best tutorial for beginners. It's  
fine for the programmer experienced with another language or 2, but  
it does make an excellent place to look things up when you have  
questions.

If you're a super beginner, check out Learn to Program, by Mr. Pine.  
It's a gentle introduction.
If you're interested in a wild ride, check out Why's Poignant Guide .

The Ruby Cook Book is also interesting to have around. It's only  
weakness is that it covers Rails while there is also a Rails  
cookbook. It should have gotten on some of the topics covered in the  
Perl, Python, and PHP cookbooks.