I will discuss the first results of the Exploration Science program GOODS Re−ionization Era wide−Area Treasury from Spitzer (GREATS), which provides ultradeep (200+ hour / pointing) Spitzer/IRAC observations of normal L* galaxies at 7 < z < 11 in the GOODS-North and GOODS-South fields. New constraints on stellar masses, SFRs, high equivalent width emission lines, and photometric redshifts are presented. I will assess implications for the early build up of galaxies and future observations with JWST.