In a fractional rating system, I would have given this book a 3.7.Sometimes I pick up a bunch of books really cheap, for ten cents apiece up in Maine. Or I get them three for a dollar in Brookline. At those prices, I can afford to take a chance on writers that I've never read before - even though I only like three modern genre writers.Once in a very long while, I find a new modern author who can write well.The Vigilant is actually a surprisingly good book. Gardner's not a new Zelazny, but this long science fiction novel about a plague on a colony planet surprised me several times - and didn't annoy me once. Well, okay, the author's use of the word "Dads" annoyed me. A lot. But apart from that, the characters were well-written, and the plot worked pretty well.The heroine was a bit annoying at times, but that was intentional. And the ideas behind the story were interesting; it takes place in a galactic "League of Peoples" in which unimaginably powerful races have issued a single command: that dangerous non-sentient beings cannot travel from planet to planet.The novel also features an interesting idea for a non-governmental organization which exists solely to scrutinize the government, and to publicize malfeasance and the consequences of government action and inaction; it's not slanted in any obvious political direction, and doesn't pretend to perfection.There's a pretty large mystery component to the plot, which when handled properly is always good. I don't know if it would have been possible to solve the mystery before the denouement, but I didn't feel cheated, and I didn't see the various revelations coming in advance. Apparently Gardner has written a number of other books; I'll probably try them.