This document serves as the summary report on the first year’s progress on the Architecture Development Facilitator (ADF) project covering the activities from December 15, 2005, to December 15, 2006. The ADF is intended to assist the Office of Network Coordinator for Health Information Technology (ONC) of the Department of Health and Human Services (HHS) and its agents in the deployment of the Nationwide Health Information Network (NHIN). ADF will serve as the repository of a set of predefined compatible health care IT components, called artifacts, which can then be combined to design, configure and deploy a large variety of health care IT system architectures. The design of ADF responds to the evolving nature of the NHIN by making absolutely no assumptions about the upper levels of the NHIN architecture and by not imposing any constraints on the architecture. An artifact is defined in ADF as either: (a) a service or system component of NHIN (service artifact) or (b) a unit of information interchanged between service artifacts (information unit artifact). Artifacts are represented in the ADF by a generic template applicable to all artifact types, type-specific template extensions for each type, and by the relationships between the artifacts. An example of the representation is presented in terms of the harmonized use cases released by the ONC. A sampling of distinct network architectures that may be configured from the sample set of artifacts is presented for illustrative purposes. Initial thoughts are summarized on a number of architectural issues considered during the past year that have not yet been fully developed, as well as the directions for the work we expect to undertake in the second year of the project.