The early-20th-century houses designed by architects Charles Sumner Greene and Henry Mather Greene combined the “greatest possible amount of Truth with the greatest amount of Pleasure.” Their hand-hewn architecture descended from the English Arts and Crafts movement, paralleled the Craftsman house, and foretold the common American bungalow. With a design vocabulary that revolved around cobblestone, oak, redwood, cedar, iron, and leaded art glass, among other elements, Greene and Greene let their materials and structures speak for themselves in such masterpieces as the Gamble House in Pasadena, Calif. Edward R. Bosley, who serves as director of the Gamble Housewhich survives today as a public sanctuary to organic designhas recently completed Greene & Greene: Masterworks, a monograph on the designing brothers, and will talk about the reasons their mystique endures long after the Industrial Age overwhelmed it. At 6:30 p.m. at the National Building Museum, 401 F St. NW. $12. For reservations call (202) 272-2448. (Bradford McKee)