Marathons have become too easy for some runners. What was once the pinnacle of achievement in a runner's life is now a stepping stone for extraordinary adventure in ultramarathoning. The number of ultrarunners--those running distances of 50k (31 miles), 50 miles, 100k (62 miles), or 100 miles--is growing astronomically each year. Dean Karnazes' Ultramarathon Man and Chris McDougall's Born to Run have inspired tens of thousands to try these seemingly superhuman distances. But to date, there has been no practical guide to ultramarathoning. Now, Bryon Powell has written Relentless Forward Progress, the first how-to manual for aspiring ultrarunners. Powell covers every aspect of training for and racing ultra distances. Along the way, more than a dozen elites and experts, including Geoff Roes, Krissy Moehl, Michael Wardian, Dave Mackey, and David Horton, provide invaluable advice on running ultramarathons. By its conclusion, this encyclopedic volume prepares runners for going farther than they have ever gone before and, in the process, shows them that they are capable of the "impossible."