“Perfection.” The cryptic word, inscribed above the entry of a stately, Corinthian-columned building on Fullerton Avenue near my old apartment, always perplexed me. Whose “perfection” was this? Who put the word there, and why? I eventually did some digging and found out that the building had been home to a Depression-era lender, Fullerton State Bank, before being sold in the 1930s to—who would ever have guessed?—the Perfection Burial Garment Company, which emblazoned its name on the archway above the front door. There are dozens of similar riddles waiting to be solved all over Chicago—single words engraved above the entrance of prewar buildings, meant to preserve a legacy now all but forgotten: “Essanay” on Argyle Street, “Leroy” on Reta Avenue, “Overton” on State Street. Sometimes the mystery is easy enough to crack: The building on Argyle, for one, was named for Essanay Studios, a production company that made more than 2,000 films between 1907 and 1917, including 15 starring Charlie Chaplin. The origins of others seem to have been lost in the mists of time.