The Soviet-American strategic arms limitation discussions and agreements have been widely welcomed not only as important steps toward tighter arms control but as a symbol of die entire process of East-West détente. For die first time since 1945, the two superpowers have shown themselves willing to put agreed limitations on their central strategic armaments. The SALT I talks imposed rough numerical ceilings on deployment. One of die major difficulties in the attempt to extend these limitations in SALT II is die formulation of qualitative restraints. Each side is under pressure to create improved weapons systems. Each is concerned lest the odier should achieve a breakthrough which would render its own systems ineffectual. Each needs to hedge against the possibility that the other might design around any particular set of arms control arrangements. In this paper I will examine die desire for innovation and die difficulties of control, and suggest a general framework within which the question of limitations might be further examined. In the first part, I will discuss the meaning of innovation and the ways in which it is organized and promoted. In die second, the reasons are examined why the two great powers seek advantages over each other in the area of R & D. Finally, I will look at some of the difficulties of achieving restraint by agreement and under verifiable conditions.