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Abundances of elements comprising solar energetic particles (SEPs) come withtwo very different patterns. Historically called "impulsive" and "gradual"events, they have been studied for 40 years, 20 years by the Wind spacecraft.Gradual SEP events measure coronal abundances. They are produced when shockwaves, driven by coronal mass ejections (CMEs), accelerate the ambient coronalplasma; we discuss the average abundances of 21 elements that differ fromcorresponding solar photospheric abundances by a well-known dependence on thefirst ionization potential (FIP) of the element. The smaller impulsive("3He-rich") SEP events are associated with magnetic reconnection involvingopen field lines from solar flares or jets that also eject plasma to produceaccompanying CMEs. These events produce striking heavy-element abundanceenhancements, relative to coronal abundances, by an average factor of 3 at Ne,9 at Fe, and 900 for elements with 76<Z<82. This is a strong, power-lawdependence on A/Q with a ~3.6 power when Q values are determined at coronaltemperatures near 3 MK. Small individual SEP events with the steepestenhancements (~6th power of A/Q), from ~2.5 MK plasma, are associated with B-and C-class X-ray flares, and with narrow (<100 deg) CMEs. Enhancements in3He/4He can be as large as those in heavy elements but are uncorrelated withthem. However, events with 3He/4He > 0.1 are even more strongly associated withnarrow, slow CMEs, cooler coronal plasma, and smaller X-ray flares. Theimpulsive SEP events do not come from hot flare plasma; they are acceleratedearly and/or on adjacent open field lines.

Element abundances in solar energetic particles: two physical processes, two abundance patterns