This book reviews different aspects of the cancer microenvironment, and its regulation and importance for tumor progression. Methodological advancements and practical applications, in terms of how biomarkers are studied and increasingly included in clinical trials and therapy protocols, are described and discussed.  Biomarkers of the Tumor Microenvironment is an educational resource for students and members of the cancer research community as a whole, especially for those using morphology analysis techniques and models focusing on the cross-talk between different cell types in tumors. The textbook provides a comprehensive overview of the microenvironment in various contexts from the perspectives of experienced and accomplished cancer researchers and clinicians.