Antibody-directed enzyme prodrug therapy (ADEPT) directly addresses the major problem in cancer chemotherapy-its lack of selectivity. Antibody delivery combined with the amplification provided by the enzymatic activation of prodrugs enables selection to be made between tumour and normal tissue. ADEPT offers a novel field of opportunities in the therapy of systemic cancer and may be a major advance for the treatment of solid tumours. This book is the first to describe ADEPT in detail. Each chapter reviews an aspect of the immunology, enzymology, biochemistry, chemistry, and cancer chemotherapy which have been integrated into the ADEPT concept. An additional chapter describes the related approach of gene-directed enzyme prodrug therapy (GDEPT). This latter approach is still in its infancy but ADEPT has entered the clinic. The initial clinical studies with ADEPT are included and discussed in detail.