From The Yale University Library Gazette archive:

THE JAMES WELDON JOHNSON MEMORIAL COLLECTION OF NEGRO ARTS AND LETTERS by Arna Bontemps

originally published in,Vol. 18, No. 2 (October 1943), pp. 19-26

An excerpt:

“Mr. Van Vechten, who had already formed the habit of aiding and abetting genius (he had much to do with the establishment of such careers as George Gershwin’s and Igor Stravinsky’s, and he contributed to the revival of Herman Mel- ville), was actively involved in the launching of Paul Robeson and Ethel Waters. He showed Langston Hughes’s poems to Margaret Case at Vanity Fair and to Alfred A. Knopf the publisher. These instances are merely typical, but they account for the great quantity of Robeson lore, the complete set of Ethel Waters phonograph records (some of them unusually rare), and the boxes and boxes of Langston Hughes’s letters and first drafts.”