Seabury Press, AN EPISCOPAL DICTIONARY OF THE CHURCH (Don S. Armentrout & Robert Boak Slocum, eds.), https://www.episcopalchurch.org/glossary/seabury-press/:
A church-owned publishing house that was sold in 1984. Lewis Bliss Whittemore (1885-1965), Bishop of Western Michigan, called attention to the lack of progress in Christian education throughout the Episcopal Church in 1946. The result of his action was a revitalized, reorganized Department of Christian Education, which began a project called the “New Curriculum,” now known as the Seabury Series. As the project developed, an agency was needed to produce and publish the books and pamphlets. In 1951 the National Council (now the Executive Council), established the Seabury Press. On Sept. 1, 1951, Leon McCauley was appointed the first Manager of Seabury Press, named after Samuel Seabury, the first American Episcopal bishop. It officially opened for business on Jan. 2, 1952. Seabury Press was incorporated in Feb. 1952 with the Presiding Bishop as Chairman. Although responsible to the Department of Christian Education, it received no funds from the church's budget. Beginning in 1953, Seabury Press published Prayer Books and Prayer Book/Hymnal combinations. Seabury Press was a publishing house, not a printing plant. It designed books and book jackets as well as getting manuscripts ready for publication. Seabury Press went out of business in 1984. Winston Press acquired its publishing assets. See Seabury, Samuel.
Press Release, Episcopal News Service, Winston-Seabury Press Sold To Harper & Row (Feb. 27, 1986), https://www.episcopalarchives.org/cgi-bin/ENS/ENSpress_release.pl?pr_number=86039.