Hood pioneered the systems biology concept of considering human biology as a "network of networks." In this model, understanding how systems function requires knowledge of: (1) the components of each network (including genetic, molecular, cellular, organ networks), (2) how these networks inter- and intra-connect, (3) how the networks change over time and undergo perturbations, and (4) how function is achieved within these networks. At the ISB under Hood's direction, genomic, transcriptomic, metabolomic and proteomic technologies are used to understand the "network of networks" and are focused on diverse biological systems