Television: a producer's medium; The Producer's Medium, by Horace Newcomb and Robert S. Alley. New York: Oxford University Press. 253 pp. $17.95

Most television books are either encyclopedic references or nostalgic scrapbooks. Horace Newcomb and Robert S. Alley have tried for something different. Just as the playwright is recognized as the creative force in the theater, and the director has been lionized as the ''author'' of the movies, Newcomb and Alley present a convincing argument for looking at television as the producer's medium.

To back up this viewpoint, the authors present interviews with 11 producers ranging from Quinn Martin (''The F.B.I.,'' ''The Streets of San Francisco'') to Garry Marshall (''Happy Days,'' ''Mork and Mindy''). The producers discuss such issues as their social responsibility for the contents of their programs - and whether their shows demonstrate a personal style. Instead of creating another book strictly for fans of a particular show, the authors give us the creative minds behind some of the best programs of the last 20 years, talking about their work.

Because it takes television seriously as an art form, this thought-provoking and informative book will interest anyone interested in television. The only major flaw is that the publishers seem not to have employed any proofreaders. The occasional typographical errors are annoying enough. There is no excuse, however, for such misspellings as Hal Wallace (for Hal Wallis) or Harry Cohen (for Harry Cohn).

This book shows that television is a lively art. Is copy editing a dead one?