Notes:
SZ surveys can place constraints on the "quintessence" equation of state parameter w, with uncertainties comparable to those that could be obtained by the Supernova Acceleration Project (SNAP, 2000 SN1a per year) or the Deep Extragalactic Evolutionary Probe (DEEP) Redshift Survey (Davis & Faber 1998, spectra of 60,000 galaxies at z>0.7). Quintessence, unlike the cosmological constant, might be a dynamic, time-evolving and spatially dependent form of energy with a negative pressure sufficient to drive the accelerating expansion of the Universe.