Suppose a student sought a Crystal textbook, then found the Pragmatic Bookshelf work slender (or perhaps behind the time), and the Packt Publishing offering guilty of association with Packt Publishing.
Maybe the student thinks: “Given the similar syntax, a Ruby book could be helpful, and there are many of those”. Could any Ruby book be recommended for hewing more closely to Crystal than others?
I bought the Packt pub Crystal book a few days ago after a couple of weeks only using the resources on the Crystal Website. I find it well written, and within the first few pages had learned some things about Crystal that I hadn’t known. I’d recommend it if you have the means to purchase it.