He was 75. He had been in the hospital for a lung infection.
Mr. Furth was a not particularly successful actor when he began jotting down ideas for a series of one-act plays, with the idea of getting actress Kim Stanley to play the lead in each playlet. When no producer would bite, he turned to Sondheim, who in turn showed the work to director Harold Prince. Prince said, "Let's make a musical out of them." That's what they did, employing three and a half of Mr. Furth's plays, with the writer contributing one and a half new plays as well. The result was 1970's Company, the first of several landmark concept musicals Prince and Sondheim would collaborate on. Mr. Furth's vignette format is still very much apparent in the thematic tale of marriage, love and commitment as seen through the anxieties of the eternally single Bobby.
Critics largely applauded the boldly modern musical and it ran 690 performances on Broadway, winning the Tony Award for Best Musical. Mr. Furth also won a Tony for his book.
Mr. Furth used some of the one-acts not used in Company to form Twigs, a 1971 quartet of interconnected plays about four women, all from the same family. Sada Thompson portrayed the women. The play won mixed reviews, but nevertheless ran 289 performances.
Mr. Furth's other plays included Precious Sons and The Supporting Cast. He also wrote the book for the John Kander and Fred Ebb musical The Act. His most peculiar writing credit may be Getting Away With Murder, a third collaboration with Sondheim. A comedy thriller that ran a few weeks in 1996, it was a rare stab at straight playwriting for the composer, and one of the last examples of the thriller genre to reach Broadway.
In the late '90s, there was talk of Annette Bening starring in Mr. Furth's comedy Sex, Sex, Sex, Sex, Sex, Sex, Sex, but the production never materialized.
Born George Schweinfurth in Chicago on Dec. 14, 1932, George Furth attended Northwestern University, and spent the first couple decades of his professional life as an actor, appearing in such movies as "Butch Cassidy and Sundance Kid," "The Boston Strangler," "Shampoo," "Sleeper" and "Myra Breckinridge" and the television shows "The Defenders," "The Farmer's Daughter," "Honey West," "F Troop," "The Monkees" and "McHale's Navy."
A somewhat elusive figure whose pictures always showed him flashing the same nervous grin, Mr. Furth rarely gave interviews. This fact, he said, was partly the reason for his personal popularity. At the opening night party of the 2008 Broadway revival of Company, he whizzed by reporters without a comment. "I just don't do interviews," he explained. "That's why I have so many friends."