The microenvironment in which a tumor originates plays a critical role in its initiation and progression. Tumor Microenvironment reviews the importance of tumor microenvironment in cancer management. Particular emphasis is placed on discussing how the unique characteristics of the tumor microenvironment not only impact disease progression and response to conventional anticancer therapies, but have also led to the identification of potential new therapeutic targets and treatment possibilities for cancer patients. Tumor Microenvironment also reviews the fundamental basis of target development, preclinical assessment, and the current clinical status of these therapies.