"During the first half of this century most syntheses were developed by selecting an appropriate starting material, after a trial and error search for commercially available compounds having a structural resemblance to the target of synthesis. Suitable reactions were then sought for elaboration of the chosen starting material to the desired product. Synthetic planning in most instances was strongly dependent on an assumed starting point. In the fall of 1957 I came upon a simple idea which led to an entirely different way of designing a chemical synthesis. In this approach the target structure is subjected to a deconstruction process which corresponds to the reverse of a synthetic reaction, so as to convert that target structure to simpler pecursor structures, without any assumptions with regard to starting materials. Each of the precursors so generated is then examined in the same way, and the process is repeated until simple or commercially available structures result. This “retrosynthetic” or “antithetic” procedure constitutes the basis of a general logic of synthetic planning which was developed and demonstrated in practice over the ensuing decade."