The Johns Hopkins Medical Institutions and the Enoch Pratt Free Library joined forces in 2000 to study the development of a new 20,000 square foot branch library at the southeast corner of Orleans Street and Broadway in east Baltimore. The new building needed instructional and study facilities for The Pratt Center for Technology Training, office and conference space for the Office of School and Student Services, and a generous allotment of space for children?s after school activities. In this proposal for a new building, considerations of privacy and comfort, of daylighting and night lighting, and of the nature and use for each principal space, determine the degree at transparency of the exterior walls. Parallel with the Pratt?s embrace of new technology in their service delivery, the proposed building incorporates emerging construction technologies to enhance environmental control and reduce energy use. The largely glass exterior of the building is proposed as a multilayered wall to the south and west, engineered to control heat gain in the summer and to capture solar heat through the winter.