Triggered in part by a trip to the Galápagos Islands, the author interweaves two parallel narratives: Darwin's "journey toward evolution" along with the related work of Alfred Russel Wallace; and the author's own journey through life, partially disabled and dependent on the specially fitted shoes that help him to walk.  Together these two narratives develop "all I have come to understand about chance and change, fear and transformation, variation and cultural context, ideas about the body that question the definition and existence of difference in all of our lives" (xvii).

Born with an unnamed congenital condition in which his fibulae are absent along with other lower limb "abnormalities," Fries underwent five major reconstructive surgeries as a child, but after those, what helped him most were special shoes that were fitted to his special body, assisting him to walk.  As an adult, however, he begins to experience back pain and knee problems.  The memoir relates, both in flashback, and in the present day, Fries's quest for a proper pair of shoes that will help him avoid yet another surgery -- the shoes he has been wearing are 20 years old and no longer do the job.  We meet Dr. Mendotti, who treated him like a peculiar specimen and offered a pharmacologic way out of his pain; shoemaker Eneslow, in a dingy Union Square office, whose shoes not only fit Fries well, but were festive in appearance -- "I felt both normal and special" (17); other practitioners of orthotics who try but fail to construct shoes that relieve Fries's pain, and finally, the gifted, patient orthoticist, Tom Coburn, who persists until he is able to provide shoes that work.  The shoes have been adapted for Fries's body, just as man has constructed adaptations that allow him to live in a variety of climates and circumstances.  Conversely, Fries, convinced he "can adapt to the circumstances in which my body places me (169)," draws from Darwin, whom he quotes: "individual differences are highly important for us, as they afford materials for natural selection to accumulate" (169).
 
Darwinian connections are invoked throughout the narrative.  The peculiar configuration of Fries's feet and shoes help him to ascend a series of mountain ladders while his partner, Ian -- who usually has to assist Fries with such physical maneuvers -- suddenly becomes fearful of the height and exposure;  back problems might have developed even without his congenital abnormalities because evolution of the capacity to walk upright included the tendency toward back pain; the role of chance in natural selection and the role of chance in the physical fact of congenital conditions; the positive role that his partner Ian's attention deficit disorder (ADD) could have played in the days of hunter-gatherers and the cultural context in which ADD is now considered to be "abnormal."
 
Fries discusses his fears -- both rational and irrational -- as well as his awareness of stigma, difference, and sameness.  The context of these discussions is usually a reminiscence about vacations in far-flung countries (Thailand, the Galápagos, Bali, Alaska, the Canadian Rockies) and physically challenging domestic locales (a Colorado River raft trip, the Beehive Mountain in Acadia National Park).  He  occasionally brings into the discussion his homosexuality, especially as his physical deformity affected sexual encounters.  The relationship between Fries and Ian is woven throughout the memoir as one of understanding, mutual need and benefit.  As the memoir ends, Fries worries about the likelihood he will need a wheelchair, but is at the same time gathering confidence in his ability to ride the Easy Flyer bicycle that Ian has discovered at the local bike shop.