Pathway Logic [3, 4, 8] is an application of techniques from formal methods to the modeling and analysis of signal transduction networks in mammalian cells. These signaling network models are developed using Maude [1, 2], a symbolic language founded on rewriting logic [5]. Network elements (reactions) are represented as rewrite rules. Models can be queried (analyzed) using the execution, search and model-checking tools of the Maude system. Collections of rules and initial states of interest form a novel kind of database where a biologist can record results of both curation and experiments.