At Princeton University, an architect unites two disciplines with splashes of daylight and easy sociability.

The design for a convention center in central Spain's historic city of Toledo presented Rafael Moneo with a fascinating problem: how to insert a modern, 400,000-square-foot building into a city that has scarcely changed since El Greco painted it in the 16th century.

According to Rafael Moneo, who designed the Gregorio Marañon Maternity and Pediatrics Hospital in Madrid with specialist José María de la Mata, a hospital “should be clear, clean, and luminous.