Protector

The first half of this book was published separately in 1967 and is a classic tale of first contact with another intelligent species (the Pak). It has sense of wonder, great ideas, humour, pace, everything. The human characters are not great, but they're varied and have some degree of humanity.

Some years later, Niven decided to write about what happened next, and the book got its second half, which is set a couple of centuries later! It remains well thought out, imaginative, and interesting in a dry sort of way, but some of the magic and the pace have gone out of the story, and it turns into rather an academic exercise. There are only a few significant characters and even the author doesn't seem to care much about any of them.

I give it four stars overall because the first half is great and the second half is still worth reading, although for me it's relatively disappointing as a story.

Quite early in his career Niven came up with some great ideas for alien species, most notably the Thrintun, the Pak, and the Moties. I think the Thrintun appear in only one novel, but the Pak turn up again later in some other books.