Flare precursors and onset

We report on the progress of a search for precursors that have direct physical connections to the start of subsequent solar flares. The discussion includes recent results at radio, visible, ultraviolet, and x-ray wavelengths, which are relevant to the pre-impulsive (onset) phase. We also relate the aspects of a theoretical scenario, based on magnetic reconnection with transport-coefficient phase changes, for explaining flare onset. The pertinent time scales for pre-impulsive temporal developments are discussed.