MCA -- originally the Music Corporation of America -- was started in the 1920's by Jules Stein. An opthamologist with a dance band on the side, Stein found he had two bookings one night and, instead of turning one down, he booked another band, took a 20 per cent fee, and began what would turn out to be the world's largest talent agency.

By the 1930's MCA represented an estimated two-thirds of the country's big bands, and was able to use this leverage to package radio programs with its talent and get exclusive hotel bookings. MCA moved into Hollywood in the 1930's and had a similar success signing studio talents. Its power to withhold stars was such that MCA was reputed to be able to dictate casting.

The company was quick to embrace television in the early 1950's and became a major series producer. And in 1959 it bought the dilapidated but huge Universal Studios and became a major motion picture producer.

The Justice Department in 1961 accused MCA of monopolizing the entertainment business with its dual role as talent agency and giant film and TV producer and made the company divest itself of the agency.

Stein, 80, who retired as MCA chairman in 1973, still occupies the entire top floor of MCA's black headquarters building here, known as the "tower of fear," and comes in virtually every workday. He still owns 20 per cent or about 3.4 million of the company's outstanding shares, trading recently at $37.

Hard - driving Lew Wasserman, who joined the company as an agent at age 22, became president in 1946 and chairman when Stein retired. He owns 10 per cent of MCA shares, with other sizable blocks held by other company executives and employees.