New libraries of molecular knowledge continue to appear as molecular biology races forward. The May 3, 2012 issue of Cell brings a new paper reporting that European researchers searched for and appear to have found all proteins that bind to mRNA. This important work arises from a comprehensive study of proliferating HeLa cells. The findings include 860 proteins, with new discovery of over 300 proteins. Defining the universe of proteins is an important step in understanding the workings of our cells and genomes. A press release provides additional color and links; the work is part of the ongoing efforts of the European Molecular Biology Laboratory.