When John Baldessari was looking for an L.A. gallery to show his work 20 years ago, he narrowed his choice to three and ultimately chose Margo Leavin.

"I thought she would be around for a long time," he said. "And it turned out to be true."

For more than four decades, Leavin has occupied a prominent perch in the Los Angeles contemporary art scene. Her gallery, which opened in 1970, is one of the most enduring and recognizable in the city, with a roster of top-tier artists that includes Jeffrey Vallance, Alexis Smith and William Leavitt as well as Baldessari.