The phenomenon of transition in a laminar flow has been a topic of continued interest for many years. Recent experiments in shear flows have revealed a series of instabilities that lead to breakdown to turbulence. We have completed an analysis of the mechanisms which drive the primary (TS wave) and secondary instabilities in plane Poiseuille flow. This was accomplished by studying the solutions of linear primary and secondary stability theory with energy methods. We found that primary instability occurred when the viscous stresses overpowered dissipative forces near the channel walls. For the secondary instability, we saw that the TS wave catalyzes the instability and then mediates the transfer of brge amounts of energy from the mean flow into the three-dimensional disturbance, thus driving the instability. In addition, we have compiled an extensive catalog of the loc!l.l energy and vorticity field distributions which result from each instability. / Master of Science