Genzyme Center is the corporate headquarters for a biotechnology company, with offices, an employee cafeteria, a library, gardens, training rooms, a conference center, cafes, and public retail space. The design goal was to develop a building from the inside out, from the individual working environments to the overall complex structure of the building. Largely due to the collaboration of the design team, developer, client, and construction team, this led to an environmentally friendly, highly communicative, and innovative signature building. The project team and the client balanced aesthetics, cost, constructability, and reliability to create an environmentally responsible corporate headquarters. A number of environmental design strategies contribute to the LEED Platinum rating the building has achieved and establish an open spatial atmosphere for the building occupants. The building envelope is a high-performance curtainwall glazing system with operable windows on all 12 floors. More than 32% of the exterior envelope is a ventilated doublefacade that blocks solar gains in summer and captures solar gains in the winter. Steam from a nearby power plant is used for central heating and cooling. The building’s central atrium acts as a huge return air duct and light shaft. Fresh air moves into the atrium and up and out through exhaust fans near the skylight. Natural light from the fully glazed facade and from the atrium brought in by solar-tracking mirrors above the skylight is reflected deep into the building. The building uses 32% less water than a comparable office building by using waterless urinals, dual-flush toilets, automatic faucets, and lowflow fixtures.