The key feature of enzymic catalysis is recognition of the transition state. Synthesis of designed systems rarely leads to successful catalysts as the rules for conformation and intermolecular interactions are to imperfectly understood. This review describes several current ‘selection’ approaches to the generation of systems that can recognise transitionstate analogues. Examples covered include catalytic antibodies, ribozymes, imprinted polymers. Combinatorial chemistry, and thermodynamic templating. All have the potential to yeild effective catalysts without prior design of every detail.