There has been a virtual explosion of information relating to the biology of sarcomas with which we as orthopaedists deal. Much more is yet to be learned. These findings will teach us more about the etiology of these tumors. More important, the findings will alter the way in which these tumors are treated. It is unlikely that we will continue to treat osteosarcoma or Ewing's sarcoma patients with currently available drug regimens and surgery or make treatment decisions based on the histologic classification of tumors we know today. If we are to remain active in the management of these patients we must be aware of the findings as they occur. That will ensure both that we remain the primary caretakers of these patients, and that we will continue to be stimulated intellectually by these intriguing scientific investigations.