The End of the Dinosaurs

It is now the consensus that 65 million years ago there was a major impact which caused a major extinction. In The End of the Dinosaurs:Chicxulub Crater and Mass Extinctions Charles Frankel describes how this idea came to be accepted.

The book starts with a look at how gradualism used to be the dominant idea in geology and paleontology. The evidence against it started to stack up though. In the rock layers delineating the geological timescale, there was a suprisingly thin layer when the Cretaceous gave way to the Tertiary (K-T boundary), implying a dramatic change over a relatively short time. Furthermore, this layer had an excess of iridium, implying a connection with meteoritic material. Tektites - small blobs of rock which had melted - also supported the impact hypothesis. But there was still much resistance to such an outlandish idea until the Chicxulub crater was discovered. Frankel explains how things then fell into place. He goes on to describe what would have happened following the impact, and in the last couple of chapters looks at other impacts, including candidates for other mass extinctions as well as those which have occurred within human history.

If you're looking for a book about dinosaurs, then this might not be for you - it's more a book about extraterrestrial impacts. It's well written, giving an easy to follow account for the non-specialist, but also giving an insight into the working of the scientific world, and how a controversial topic is dealt with.