Timeline by Michael Crichton. From about page 39 I was totally hooked. Wild ride! Crichton takes a concept and researches in completely (bibliographies in the back) and then weaves a story around it. This book combines Medieval England and Quantum physics. I try to read one of Crichton's book's each year. State of Fear was very interesting with a plot that revolved around politicizing science.
While Crichton can be formulaic in his writing, I really got a great deal of enjoyment from this book. I'm a sucker for any story about time travel and the swashbuckling was surprisingly captivating. It's unfortunate that the movie was such a waste of time.