The Ringworld Trilogy spans the books: 'Ringworld', 'The Ringworld Engineers' and 'The Ringworld Throne'. They are without doubt some of the most spectacular science-fiction novels ever written, not only for their level of characterisation, but the depth to which Niven has researched into the scientific fields.

The Ringworld of the series is precisely that, a huge scrith (a metal Niven creates for the series) ring that holds a world inside it. But that's not even close, the size of the world is unparalleled and for the explorers a wonder and a threat together.

The three species of explorer are man, kzinti (big furry hunter warrior types) and puppeteers (they have two heads, three legs and a bouncy ball shaped stomach connecting them all). The main character of all three novels is Louis Wu, the 200 year old human who embarks on the first quest to the Ringworld, only to leave and return once more with new companions.

The two kzinti of the novel are Chmee, and later his son, Acolyte. The kzinti are a war-like race who have been evolved into diplomats by constant war with men. Fortunately for men, we keep winning. The puppeteers in the novel are Nessus and Hindmost, and they are both by their own species definition, mad.

And so over the course of the three novels they slowly explore the Ringworld, and there's a lot to be explored. The interior of the Ringworld holds enough space for 100 earths with room to spare, there is even a 'map' of earth, as well as mars and other planets - including the kzinti homeworld.

With this and other mysteries to solve, including the presence of 'Fist-Of-God', a giant meteoric hole punched through the ring, the pace of the books never lets down. After Star Wars (could there be any other?) Larry Niven's series remains one of my favourites and I heartily recommend it to anyone, although you might find it difficult to understand some of the physics behind it if you haven't studied beyond a certain level.

A good thing about this is that Niven doesn't let it carry the story away, and in 'Throne' there's a superb glossary of terms, dramatis personae, and even the measurements for the Ringworld itself. If you need a good dose of science fiction then these are the books to try.

Yoda