Dore Ashton, an art historian and critic who wrote some of the earliest and most insightful histories of Abstract Expressionism and the leading painters of the New York School, died on Monday in the Bronx. She was 88.

Her death was confirmed by her daughter Paris Marina Devereaux.

Ms. Ashton was closely involved in the small world of artists who were discovering a new pictorial language in the years after World War II, both as a friend of Philip Guston, Mark Rothko and others and as a reviewer for numerous publications, including Art International, The Art Bulletin and The New York Times.

She recorded the scene, and she inhabited it. She made a point of visiting artists in their studios, drinking with them at their favorite haunts and talking philosophy and aesthetics into the wee hours in downtown cafes.

In a clear, pithy style, Ms. Ashton wrote both sweeping histories and intimate studies devoted to individual artists. Her books “The Unknown Shore: A View of Contemporary Art” (1962) and “The New York School: A Cultural Reckoning” (1973) made the case for Abstract Expressionism as the pre-eminent postwar art movement and placed its disparate members into a coherent philosophical frame.