Book excerpt: This fresh and fascinating exploration of new directions in cancer research focuses on the important role of the immune system in combatting this dread disease. Integrating clues from the animal kingdom, the veterinary clinic, extraordinary human cases, and even embryology, the author-a cancer physician, biologist, and physicist-creates a novel and compelling account of tumor immunology and the promises of immunotherapy. As the author explains, animals offer us many tantalizing clues about the nature of cancer in humans. Tasmanian devils are on the verge of extinction due to a virulent form of contagious cancer; soft-shelled clams on the East coast of North America are vanishing due to another epidemic of contagious cancer; dogs also contract a contagious cancer but they spontaneously overcome it; and a type of mouse and the homely mole rat are not susceptible to the disease at all. In humans, there are rare instances of spontaneous cures of advanced cancers induced by radiation. An uncommon form of dwarfism called Laron syndrome confers total cancer immunity on the people who inherit the condition. And recent research suggests that cancer has stolen the secret that shields the embryo against hostile attacks from the mother's immune system. The author makes a convincing case that what all of these diverse examples have in common is the immune system and its ability or inability to respond to malignancies. He concludes with a review of the exciting research on the human immune system and the development of new treatments that are inducing the immune system to combat and conquer even the deadliest cancers.