Dean Karnazes has run 350 continuous miles through three sleepless nights, ordered pizza during long runs, and inspired fans the world over with his adventures. So what does a guy like this do when he wants to face the ultimate test of endurance? He runs 50 marathons in 50 states-in 50 consecutive days.

With little more than a road map and a caravan packed with fellow runners and a dedicated crew, Dean set off on a tour that took him through a volcanic canyon in Maui in high humidity and 88-degree heat; to an elevation gain of almost 4,000 feet at the Tecumseh Trail Marathon in Bloomington, Indiana; to a severed moose leg found alongside an Anchorage, Alaska, trail that compelled him to sprint for safety.

Now in this heart-pounding book, Dean reveals how he pulled off this unfathomable feat with a determination that defied all physical limitations. But Dean goes beyond the story of the Endurance 50 marathons to share his invaluable secrets and advice for athletes of all levels. These are the tips that kept Dean going during the 1,310 miles he covered and 160,000 calories he burned-while averaging sub-four-hour marathons and often sleeping fewer than four hours each night. Learn how to:

Recover more quickly
Adapt to extreme conditions
Prevent muscle cramps and overheating
Pace yourself when you "hit the wall"
Stay motivated.

Packed with practical advice and including training regimens, 50/50 will inspire you no matter what your fitness goal is, whether it's simply walking around the block, running a 10K, or completing yet another Ironman.