Seymour B. Durst, a Manhattan real-estate investor and developer who combined a passion for city history with an equally strong distaste for government involvement in land-use affairs, died at New York Hospital in May 1995. Mr. Durst had a stroke on May 12 1995 and did not regain consciousness, said his son Douglas. First as a member and later as president of the family real-estate firm, the Durst Organization, Mr. Durst became perhaps the leading assembler of the parcels of land on which office buildings were developed in east and west midtown over the last 40 years. As developers, Mr. Durst and his brothers in the Durst Organization built first on the East Side and then on or near the Avenue of the Americas in the West 40's, on sites assembled by Seymour Durst. The West Side buildings were the fulfillment of his expectation 25 years ago that Manhattan growth would move to west midtown from east midtown, where his father, Joseph, was active before him. Joseph Durst, a garment manufacturer who arrived from Austria in 1902, founded the business in 1927. During the Depression, he bought mortgages and leases on East Side commercial buildings. Seymour joined the firm in 1940 and took the title president after his father died in 1974. Mr. Durst was born in Washington Heights. He graduated from the Horace Mann School in Riverdale, the Bronx, in 1931 and the University of Southern California, where he majored in accounting, in 1935. In 1940, he married Bernice Herstein, who died in 1950 at age 32. He never remarried. Besides Douglas, of Manhattan, Mr. Durst is survived by two other sons, Robert, of Manhattan, and Thomas G., of Ross, Calif.; a daughter, Mrs. Wendy Durst Kreeger of Larchmont, N.Y.; a sister, Alma Durst Askin of Manhattan; a brother, David M., of Chappaqua, N.Y., and eight grandchildren.