In this review we discuss the concept of anti-angiogenesis, which is t
he inhibition of neovascularization. Anti-angiogenic agents are viewed
from the standpoint of their effect on various elements of the angiog
enic process, including induction of vascular discontinuity, endotheli
al cell movement, endothelial cell proliferation, and three-dimensiona
l restructuring of patent vessels. An effort is made to place the many
different approaches to anti-angiogenesis research into a comprehensi
ble structure, in order to identify problems of evaluation and interpr
etation, thereby providing a clearer basis for determining promising a
nd needed directions for further investigation.