What is still possible in midlife? Many of us reach our forties, fifties and sixties assuming that the major chapters of our lives have already been written. Careers are established, habits are set, and the opportunity for significant change may feel increasingly limited. Jeffrey Weiss challenges that assumption. At the age of 48, he ran his first 10-kilometre race. In the years that followed, he completed Ironman Arizona twice, finished a 72-mile ultramarathon, and embarked on a successful n...