I love the poignant guide! It (along with Ruby being an awesome language) got me into Ruby.

It's great because you read it because you enjoy it, and then you happen to learn Ruby in the process.

It also has some interesting analogies, examples, and ways to remember things. When talking about how block variables go inside |pipes|, he says:

I like to think of the pipe characters as representing a tunnel. They give the appearance of a chute that the variables are sliding down.

Much better at helping you remember the syntax than "block variables go in a comma-separated list which is enclosed by pipes" like you'd find in a normal book.