Book excerpt: Entertaining and inspirational, Why I Run is the new book from the founder of iRun magazine, Mark Sutcliffe. Drawing on more than five years of writing about running in newspaper columns, magazine features and blog postings, the 13-time marathon runner chronicles a journey that begins with a guy looking for a bit of exercise and evolves into running as a way of life. At once analytical, self-deprecating, enthusiastic and inspiring, Why I Run provides a fresh and rousing perspective on the rapidly growing sport that has allowed thousands of individuals to overcome challenges and fulfill their dreams, literally one step at a time. In sharing his own experiences and those of other runners who have inspired him, Sutcliffe narrates his love affair with the sport. And in the many stories ranging from stumbling through his first trail run to tumbling at the finish line of a marathon to cheering his training partner to a qualifying time for the famed Boston Marathon, every runner will find both entertainment and motivation.