This is an academic text, so your mileage may vary, depending on what you're looking for.

I found the historical chapters most interesting, there's something very captivating when reading about Dogen travelling from place to place, learning from old masters and ultimately returning to Japan. The book taught me a lot about different currents of thought regarding zazen (or sitting meditation), but it was a pretty heavy read on its own, and as a neophyte, some of the more profound insights probably escaped me.

I'll revisit the book once my understanding grows a bit.