The survey of eutectoid decomposition mechanisms in hypoeutectoid Ti- X alloys has been virtually completed. At temperatures from the eutectoid to the Ms in the Ti-Bi, Ti-Co, Ti-Cu, Ti-Ni, Ti-Pb and Ti-Pd systems, the bainite reaction is the only one operative. Among the eutectoid alloys studied, Ti-Co, Ti-Cr and Ti-Cu exhibit eutectoid decomposition essentially only by the pearlite reaction and Ti-Ni, Ti-Pd and Ti-Pt transform predominantly or only by the bainite reaction; eutectoid decomposition by either mechanism has yet to be observed (because of its exceedingly slow kinetics) in the Ti-Fe, Ti-Ir and Ti- Mn eutectoid alloys. A theoretical discussion is presented of the nucleation and growth kinetics of intermetallic compound crystals at fixed and at moving ALPHA:beta boundaries. In studies of the massive transformation, beta-alpha sub m, in Ti-Ag, Ti-Au, Ti-Si and Ti-In alloys, the composition region in which this transformation occurs in each alloy system was defined. By means of continuous cooling experiments, the enthalpy of transformation and the average rate of growth as a function of temperature were determined in a number of alloys in the four systems.