The traditional approaches to treat various cancers include chemotherapy, radiation and/or hormonal therapy. While these therapies continue to be effective in large part, they are not selective and highly toxic. There have been encouraging results in alternative therapeutic approach called antibody-mediated anti-cancer therapy, which is less toxic, more selective, and can also reverse drug/radiation resistance. Monoclonal antibodies or mAbs can be used to destroy malignant tumor cells and prevent tumor growth by blocking specific cell receptors. mAbs can bind only to cancer cell-specific antigens and induce an immunological response against the target cancer cell. The book covers the common and unique features of mAbs agains various cancer, gives the latest developments on the molecular, biochemical and genetic mechanisms of resistance by various mAbs, as well as discuss novel mAbs to overcome resistance.