Leslie E. Robertson, preeminent structural engineer and ENR’s Man of the Year in 1989, died on Feb. 11—one day before his 93^rd birthday. The cause was cancer.

Robertson was world-renowned as an innovator not only for supertall structures but for all structures. “Les was a perfect architect's engineer,” says L.C. (Sandi) Pei, a partner in PEI Architects, who worked with Robertson on myriad buildings, many designed by his late father, I.M. Pei.

Read the rest of the tribute at ENR.com.