The two volume Informing Science series is the first attempt to survey and synthesize research in the informing science transdiscipline. Part textbook, part collection of readings, the two volumes present both important research findings relating to the field and highlight fertile directions for future research. Volume One: Concepts and Systems focuses on the key building blocks of informing science. It begins with an overview of the transdiscipline, tracing its evolution from Cohen’s original proposal to its present state. Next, it considers a series of concepts that frequently elude attempts at rigorous definition. Among these: theory, research, information, knowledge and complexity. With working definitions established, it goes on to explore basic systems theory, introducing the concept of an informing system. The key elements of such systems—the channel, the sender/informer, and the receiver/client—are then examined individually. The volume concludes with two overview chapters. The first of these looks at the analysis of a basic informing system, in which a single informer interacts directly with a clearly specified client or set of clients. The last chapter extends these ideas to the more complex topologies (e.g., multiple channels, multiple informers, multiple clients, layers of informing) that are more typical in real world informing contexts.