Further exact cosmological solutions to higher-order gravity theories

This work would not have been possible without the help of a lot of people. I would like to thank my family and friends for their encouragement, my collaborators David Mota and Robert Scherrer for their hard work and my office mate Simon West for innumerable delightful lunches. Most of all I would like to thank my supervisor, John Barrow, for his constant support, his guidance and for his untiring correction of my speling and, grammar. i DECLARATION