For most people, a diagnosis of cystic fibrosis means the certainty of a life ended too soon. But for twin girls with the disease, what began as a family’s stubborn determination grew into a miracle.             The tragedy of CF has been touchingly recounted in such books as Frank Deford’s Alex: The Life of a Child , but The Power of Two is the first book to portray the symbiotic relationship between twins who share this life-threatening disease through adulthood. Isabel Stenzel Byrnes and Anabel Stenzel tell of their lifelong struggle to pursue normal lives with cystic fibrosis while grappling with the realization that they will die young. Their story reflects the physical and emotional challenges of a particularly aggressive form of CF and tells how the twins’ bicultural heritage—Japanese and German—influenced the way they coped with these challenges.             Born in 1972, seventeen years before scientists discovered the genetic mutation that causes CF, Isabel and Anabel endured the daily regimen of chest percussion, frequent doctor visits, and lengthy hospitalizations. But they tell how, in the face of innumerable setbacks, their deep-seated dependence on each other allowed them to survive long enough to reap the benefits of the miraculous lung transplants that marked a crossroads in their lives: “We have an old life—one of growing up with chronic illness—and a new life—one of opportunities and gifts we have never imagined before.” In this memoir, they pay tribute to the people who shaped their experience.             The Power of Two is an honest and gripping portrayal of day-to-day health care, the impact of chronic illness on marriage and family, and the importance of a support network to continuing survival. It conveys an important message to both popular and professional readers as it addresses key psychosocial issues in chronic illness throughout the sufferer’s lifespan and illuminates the human side of advances in biotechnology.             Even as gene therapy and stem cell research increase the chances for eradicating CF, this stirring account portrays its effects on one family that refused to give up. These two remarkable sisters have much to teach about the power of perseverance—and about the ultimate power of hope. I have been glued to my desk for the last three days, unable to separate myself from this wonderful account of medical illness and the amazing story told by these two remarkable sisters. I have just finished the last page with tears filling my eyes. [The Power of Two] is one of the best accounts of illness and coping with it that I have come across... this is a splendid addition to the literature of personal medical experience. -- Dr. Allen B. Weisse, Author of "Lessons in Mortality" Isabel and Anabel's memoir of their extraordinary battle with cystic fibrosis is at once uplifting and frightening, touching and tough, but always powerful and filled with life and spirit, alike. It is a story that we all must be moved by, grateful that these two sisters shared their agony and love with us. -- Frank Deford, Author of "Alex: The Life of a Child" It is the unfortunate habit of books on illness and recovery to rely heavily on sanitized clichés. The downs are very down, the ups sky-high. This honest and carefully observed account avoids preconceived notions of the complicated path toward an organ transplant. Describing the stages of the affliction in detail, it makes you feel you were there, suffering a pain you had heard about but never really visualized, aware that death is no longer just a concept but could come at any time, and experiencing the complex emotions that come with being saved because someone else died. For readers who have not been close to a wasting disease, it will be an eye-opener, horrifying but in the end inspiring, a tale of courage being tested all day and every day. -- Reg Green, Author of "The Nicolas Effect: A Boy's Gift to the World" One of the hardest and earliest lessons we learn is that life isn't fair. Perhaps for that reason I don't usually take to inspirational books, which often attempt to portray a particular example of misfortune as a special gift, to be appreciated for its character-building qualities, or failing that, for an advantage so mysterious that no mere mortal can discern what it might be. Fortunately, that genre is transcended by The Power of Two, an astonishing account by twin sisters born with a genetic disease that should have killed them in infancy, and almost did. But they survived that and numerous other close calls and are now in their 30's, with degrees from Stanford University, newly transplanted lungs, and a gift for writing that takes us directly into their lives. This is an intimate, brutally honest and compelling memoir. -- Jeffrey Wine, PhD., Professor of Psychology, Pediatrics and Director, Program in Human Biology, Stanford University This is an inspiring story of how two twins Isa and Ana are thriving wit