The idea that the universe started with a big bang, including a period of inflation, is the consensus view amoungst cosmologists today. However, Paul J Steinhardt and Neil Turok think differently. In Endless Universe: Beyond the Big Bang
they describe their alternative, Ekpyrotic model. Here the universe consists of two branes, and what we know as the big bang was actually the result of these colliding. This caused them to move apart, but eventually they will approach each other again, and the whole story will begin again. Hence the universe did not begin with the big bang- this is just one of a possibly infinite number of cycles.
The book examines the properties of both the inflationary big bang model and the ekpyrotic model, and along the way the authors describe their involvement in the coming together of particle physics and cosmology. The important thing to note is that this is not just an idle speculation - the ekpyrotic model agrees with current observations just as well as the inflationary big bang model. Most importantly, the authors look forward to the improvements in observations which will happen over the next few years, and should be able to decide between the two. The book is written in an easy to read style, and is not too technical. Hence I'd recommend it to anyone with an interest in cosmology, as a pointer to a possible shake-up in the subject in a few years time.