It is a well written and enjoyable book. The underlying idea of mental instead of physical evolution is interesting, and taken in an interesting direction. Sturgeon was an excellent writer, and it shows in the variety of styles he writes with here. His love for humanity also clearly comes through in this book. In the end though, it's all a little too hokey and things tie up a bit too nicely and optimistically.

So, if you like well written, hokey, and optimistic SF that is not technological, I would recommend this book.