Motherwell was the philosopher of Abstract Expressionism — the painter who, more than any of his peers, articulated in writing and in lectures what the New York School believed it was doing — and his half-century body of paintings, prints, and writings constitutes one of the most coherent intellectual projects in postwar American art.
Motherwell came to art through philosophy. His undergraduate degree, the subsequent graduate work at Harvard and Columbia, and the sustained early reading in Symbolist poetry, French and Spanish literature, and aesthetic theory gave him an intellectual foundation unlike that of any of his future peers in the New York School. The decisive intellectual encounter of his early years was with Meyer Schapiro at Columbia, who urged him to set aside an academic career in philosophy in favour of painting and introduced him to the European Surrealist artists who had emigrated to New York in the early years of the war.
Through Schapiro and the European Surrealists — Roberto Matta in particular — Motherwell entered the small downtown New York milieu out of which Abstract Expressionism would emerge. His early work absorbed Surrealist automatism and Cubist construction into a personal vocabulary that he would refine for the rest of his career, and his close working relationships with Pollock, Rothko, and Gottlieb in the early 1940s placed him at the centre of the movement's first formation.
The decisive body of work of his career began in 1948, when he produced the small ink drawing that would generate the Elegies to the Spanish Republic — the long series of black ovoids and vertical bars on white ground that became, by his own description, public laments for the lost Republican cause and for the broader violence of the modern century. The Elegies remain his most identifiable contribution to American painting and one of the most sustained single series in twentieth-century abstraction.
His parallel career as a writer, editor, and educator distinguished him from his Abstract Expressionist peers. The book series he directed brought the writings of Mondrian, Kandinsky, Apollinaire, the Surrealists, and the Dadaists into accessible English translation for the first time, his teaching shaped generations of American artists, and his published essays and lectures gave the New York School its most articulate public voice.
His later career produced the Open paintings of the late 1960s and 1970s — large planes of saturated color cut by the simple linear scaffolding of an open three-sided rectangle — and a substantial body of prints, collages, and the Provincetown-painted Beside the Sea series. His position today is settled at the highest level of postwar American art, and his work has continued to be exhibited, collected, and studied as one of the foundational achievements of mid-century American abstraction.