This is fantastic, just what I was looking for, a very quick intro to swift that assumes I'm already a programmer.

The Apple docs, at least last time I tried reading through them, were like wading through treacle so this is a great alternative! I just read the first couple of chapters in 10 minutes and got all the key info I wanted with no fluff - great job!

One edit suggestion - I've noticed a couple of times so far that "it's" is used incorrectly, for example in this sentence:

> You can’t change the type of a variable once you’ve declared it. It’s type is fixed at the time it is declared.

I assume you know the error here but on the off chance you don't:

it's = it is (it's a Bool) / its = the possessive of it (Bool is its type)

It's a little jarring so you might want to go through and fix these.

Cheers for the book! :-)