You may already have heard of it, as it's a classic in the Ruby community. It feels more like a work of art than a mere programming book, but you'll learn an awful lot while reading it. :)
As somebody who knows several other languages but not Ruby, I didn't learn that much about Ruby from that book. It's a fun read, but I felt like I mainly came away with in-jokes and minor details about syntax. I wonder if it has a bigger impact on people new to programming.
_Land of Lisp_, for example, teaches quite a bit about the language while still being fun.
It was entertaining and I found some of the clever ways he described syntax useful for remembering, i.e. the pipes form a chute which slides the variable into the block.
You may already have heard of it, as it's a classic in the Ruby community. It feels more like a work of art than a mere programming book, but you'll learn an awful lot while reading it. :)