I picked this book by Nicole Dickson off the new fiction shelf at the library, to see if it could successfully put the "knitting" into "knitting novel". Casting Off is more accurately classified as "knitting romance", but don't let that stop you from giving it a try. The main character is kind of annoying, and the storyline is equal parts predictable and unlikely, and the book is a bit long-winded, but it is redeemed by the ganseys.
Each chapter starts with a description of a gansey stitch or combination of stitches, lifted from a fictional source. Each definition also includes the meanings behind the stitches. Consequently, a gansey created with a combination of stitch patterns tells a story about the wearer. This is the most successful part of the book and makes me wish the fictional source of this information was not so fictional.
I would also call this book "beach fiction" - it will hold your attention well enough while you bake in the sand, but is not so engrossing you will lose track of the kids.