I don't consider myself a crocheter, though I do know how to crochet. It's something that I do when I find a pattern I like, need to reinforce an edge, or want to use up leftover yarn. While I enjoy the act of crocheting, I always approach it from the viewpoint of being a knitter. In this context, I've found it very helpful to have a few crochet reference books on hand and there are two in particular that I cannot do without.
The first is Stitch 'N Bitch Crochet: The Happy Hooker, which offers very clear diagrams on how to crochet in addition to 40 modern crochet patterns. The how-to section at the front of the book is particularly nice, covering everything from crocheting in the round and stitch patterns to making extras like buttonholes and pom-poms. I always reach for this book when I start a crochet project to double check that I'm doing things correctly.
The second book I recommend is Crochet Adorned, which centers around using crochet motifs to embellish everyday items. I like this book because it has a bunch of small projects, meaning that instead of worrying about screwing up, I just try things for the fun of it. The patterns themselves include earrings and pins, dress/coat/shirt trims, and a beautiful starched lace bowl. Plus, the book has a nice stitch dictionary in the back that includes different trim ideas, flower motifs, and granny triangles and hexagons.
Perhaps the flexibility of the motifs is why I like Crochet Adorned so much. For example, I made elbow patches for an old sweater using a motif that was originally intended for a table mat. Overall, the book really encourages me to explore different uses for crochet that, as a knitter, I would not have otherwise realized were possible.
I hope my book recommendations encourage my fellow knitters to take another look at crochet!