American theatrical dancing is an art that has emerged within the last hundred years. With virtually no native tradition to draw upon, the first generation of American dancers - Loie Fuller, Isadora Duncan, Ruth St. Denis - had to invent forms of their own, setting a precedent for the generations of "modern" and "post-modern" dancers to follow.

It was only after modern dance had been established as an indigenous form that American ballet came into being as a specific classic style. Though developed by a Russian, George Balanchine, American ballet was specifically adapted to the American physique and temperament. It was not simply "character" ballet with a distinctly American theme.

Concurrently there has grown up a school of American dance writers, beginning with Carl Van Vechten, who, no less than the first dancers, had to invent his own vocabulary. The present generation of American critics, writers like Arlene Croce, Nancy Goldner, Deborah Jowitt, Marcia B. Siegel, and Tobi Tobias, have in common what could be called a specifically American characteristic - they look at dance for what it is, and attempt to transmit to the reader a clear impression of how it looks, how it works.

Siegel has published two previous collections of criticism and now has written an important study of the American-ness of American dance, "The Shapes of Change," in which she gives a detailed description and analysis of some 45 works.

"A critic of dance," she writes, "is in some ways a self-appointed historian," and in this book she uses the methods of criticism to supply the material of history. She has been scrupulous about using as her examples only those dances that she could see in frequent live performances or on film, even if this meant omitting significant works like Hanya Holm's "Trend."

Not all the works she has chosen are described in exhaustive detail - sometimes she has to let the part stand for the whole. In fact, such descriptions are more evocative than point-by-point narratives. Her section on Balanchine's "Concerto Barocco," for instance, is more successful than that on Humphrey's "Passacaglia" in giving a sense of the whole piece. The book ends with a word-picture of Twyla Tharp's "Push Comes to Shove" that brilliantly conveys the wit, the consummate structure, and the liberating spirit of that extraordinary ballet.

A recurrent phrase in the book is that a work, an artist or an attitude "could only be American." One of the things that is specifically American about Siegel and her fellow-writers is the acceptance of dancing as a normal human activity that doesn't need any excuse or pretext outside itself. As a corollary, there is the refusal to make distinctions of quality, making only those of kind, between different forms of dancing - Fred Astaire is seen as no less "important" a figure than Balanchine or Cunningham.

Elizabeth Kendall's lovely book "Where She Danced" shares this point of view and explains its origin. In a sense she tells us "what has gone before" Siegel's book - how Fuller, St. Denis, and Duncan all emerged from the popular theater of their time, drawing their themes and strategies from that tradition rather than from the ballet. Kendall's book is theatrical, cultural, and social, as well as dance, histroy; these pioneers were influenced as much by related contemporary ideas of feminism, dress-reform, and physical culture as by other dance manifestations, of which indeed they had little knowledge or experience. All three dancers had arrived at their own formulations of what dance was by the time they became exposed to European theatrical dancing. Indeed in the case of Fuller and Duncan it was they who took to Europe a new vision of what dance and theater could become.

Kendall goes on to trace the linked development of dance and popular entertainment - ragtime, the follies, the movies - and convincingly argues that American dance loses an essential part of its American-ness without that connection, as, for instance, in the later works of Martha Graham in which "dance is not her main subject." Toward the end, Kendall's book overlaps Siegel's, although when she deals with Graham's "Primitive Mysteries," she compares it to Bronislava Nijinska's "Les Noces," an important analogy that Siegel misses.

For many years, as generation succeeded generation in American dance, the tendency was to deny or reject what had gone before. Only recently, and just in the nick of time, has there been a realization of the necessity to preserve what we can of the past, to retrieve dances by Duncan, St. Denis, Ted Shawn, Humphrey, and other pioneers; even Graham and Cunningham, who at one time professed no interest in preserving past works, have taken steps to do so. Both of these books reflect this new recognition of contemporary dance as part of a continuum, and in their way contribute to the process of preservation.