Once derided as a slavish admirer of Renoir, the painter and illustrator William Glackens is among the most intriguing and underestimated participants in the first wave of 20th-century American modernism. That perception is confirmed by the enlightening and overdue, if still deficient, survey of his dappled canvases and dazzling drawings at the Parrish Art Museum here. It should be required viewing for anyone interested in the period.

Glackens, who was born in Philadelphia in 1870 and educated at that city’s prestigious Central High School, was briefly affiliated with a loose group of urban-conscious realist painters known first as the Eight and later as the Ashcan School.