With the advent of state-of-the-art genomic and proteomic techniques, much has been learned about the origins and drivers of human cancers. But a solid tumor is more than a conglomerate of malignant cells that have gone awry. A solid tumor is an abnormal organ composed of cancer cells and host stromal cells, which are nourished by the vasculature and embedded in an extracellular matrix. The interaction among these cells, the surrounding matrix, and the local cellular microenvironment influences the expression of certain genes, whose products control the pathophysiological characteristics of the tumor, govern tumor progression, and affect the tumor’s response to various therapies. In recent years, some of the attempts to overcome the barriers to treatment in tumors have come to fruition and led to multiple novel therapeutic strategies. Along these lines, we are delighted to announce a special issue of The Cancer Journal, for which we serve as guest editors. It will be dedicated to the 30th anniversary Annual Tumor Course “Critical Issues in Tumor Microenvironment: Angiogenesis, Metastasis and Immunology” scheduled for October 5 to 8, 2015, at Harvard Medical School in Boston. For the last 3 decades, this course has continuously offered the best in critical analysis of what is currently known about the tumor microenvironment, metabolism, angiogenesis, metastasis, immunology, and targeted therapies. The goal has been to educate clinicians and scientists alike by highlighting key gaps in our present knowledge of cancer and outline future directions for research at the bench, in the clinic, and in drug development. Over the years, the faculty included many internationally recognized experts in these areas, including Drs Lewis C. Cantley, Peter Carmeliet, Lisa M. Coussens, Glenn Dranoff, Harold F. Dvorak, Napoleone Ferrara, Isaiah J. Fidler, Judah Folkman, Michael A. Gimbrone, Pietro M. Gullino, Richard O. Hynes, Robert S. Kerbel, Raju Kucherlapati, Robert S. Langer, Thomas Maciag, Joan Massague, Marsha A. Moses, Drew M. Pardoll, Jeffrey W. Pollard, Erkki Ruoslahti, George W. Sledge, Thomas P. Stossel, A. Gregory Sorensen, Ian F. Tannock, Thomas F. Tedder, Daniel Von Hoff, Robert A. Weinberg, Zena Werb, and Bruce R. Zetter. In the upcoming July/August 2015 issue of The Cancer Journal, some of these experts have kindly agreed to provide their unique perspectives and will summarize their latest findings from their clinics and laboratories. We think that the readership of The Cancer Journal will greatly benefit from the unique insights of these true leaders in their fields.