What's it about: Set in the year 2110, The Hammer of God revolves around the discovery by an amateur astronomer of an asteroid headed straight for Earth. Dubbed "Kali" after the Hindi goddess of death and destruction, the big space rock has the potential to wipe out life on Earth. The book follows the attempt by SPACEGUARD to prevent this by attaching a mass driver to Kali and slowly - very, very slowly - nudging it so that it'll miss Earth.
What I liked: One of the things I liked about THoG is that it didn't focus solely on the efforts of Robert Singh, captain of the spaceship Goliath and its crew to save the day. Instead, Clarke devoted a large chunk of the book to worldbuilding 22nd century human civilization and while it might at times have seemed like he was going off on wild tangents that immediately didn't seem to have any relation to the main plot, Clarke deftly tied all of these side trips together. For example, he focuses several chapters on "Chrislam", a fusion of Christianity and Islam created in the early 21st century that by the 22nd, has become the fourth largest religion on Earth. He doesn't explain any of the tenants or doctrine of the religion and you're left wondering at first as to why he devoted the two or three chapters to the religion, until near the end of the book when a fanatical faction called The Reborn sabotage efforts to divert Kali and almost wipe out mankind on Earth.