ABA’s renovation and expansion of Building 2 is the first major renewal and expansion within MIT’s 1.1m gsf Beaux Arts ‘Main Group’ building complex, completed in 1916. Fronting the Charles River with views of the Boston skyline, the 93,000 gsf Simons Building houses the Department of Mathematics. Guiding ABA’s design was the goal of balancing heritage and preservation with contemporary and changing needs. The historic limestone façade was restored and new thermally-improved steel windows installed, replicating the original windows. New building systems, acoustic improvements, and code/accessibility upgrades enhance welcome and comfort for the 675-person Mathematics community of faculty, students, and staff. New gathering and collaborative spaces, office improvements, new furnishings, and a 13,500 gsf rooftop addition merge contemporary expression with historic character, providing Department of Mathematics with a new identity that fits respectfully within the Main Group. This project is targeting LEED Silver certification.