Experiments in TFTR are making contributions to several critical problem areas of tokamak reactor design. The magnitude of tokamak plasma transport is found to be sensitive to the shape of the density profile: central peaking may be advantageous for high-temperature tokamak confinement. For moderate-Q reactor operation, the present TFTR data base suffices to solve the three main steady state reactor plasma physics problems of current drive, refuelling, and impurity control. The achievement of high Q-values at high fusion power densities is being pursued in the economically promising direction of maximizing performance at moderate plasma current. In TFTR D-T plasmas, fusion reactions due to nonMaxwellian energetic ion components will serve to generate alpha particle populations of significant magnitude, permitting the study of collective alpha-particle phenomena.