MOST AFICIONADOS of contemporary American art, especially those living in California, are familiar with the Hard-Edge school of painting, which includes artists Karl Benjamin, Lorser Feitelson, Frederick Hammersley, and John McLaughlin. In 1959 art critic Jules Langsner included them in a groundbreaking exhibition, “Four Abstract Classicists,” and defined the trend in the exhibition catalog. “Forms are finite, flat, rimmed by a hard, clean edge,” he wrote. “These forms are not intended to evoke in the spectator any recollections of specific shapes he may have encountered in some other connection.” However, many are unfamiliar with June Harwood, who was counted as one of these artists in Langsner’s next group show in 1964, “California Hard-Edge Painting.” The four artists of his first exhibition were now joined by seven more, including four…