Understanding the role of hedgehog signaling in cancer is critically important for novel cancer therapeutics. The hedgehog pathway is a major pathway regulating cell differentiation, tissue polarity, stem cell maintenance and cell proliferation. It is known by now that activation of this pathway occurs in a variety of human cancer, including basal cell carcinomas (BCCs), medulloblastomas, leukemia, gastrointestinal, lung, ovarian, breast and prostate cancers. This book provides insightful views suitable for graduate students, medical students, undergraduate students, basic and clinical scientists, cancer patients as well as the general public.