Doris Humphrey's "The Art of Making Dances" is probably one of the first dance theory books on making Western concert dance from a modern/contemporary perspective. Before her, there have been other dance theory books but they all came from classical dance thinking and for classical choreographers. This book, therefore, is definitely a milestone for contemporary dance. However, it definitely is not valuable only as a historical text - some of Humphrey's advice, insight, and criticism is still valid for today's contemporary dance world. The ones that are not up-to-date anymore, serve as a reminder of where we were and where we might go in the art of dance. Surprisingly, even though she belongs to an emotional modern dance background, she is very level-headed (obviously, she wrote a theory book) and in some instances even serves as a precursor to post-modern dance thinking. Personally, she leans on an expressive modern dance side, but to my enjoyment, in the book, she analysis the art of dance from a much more neutral and general perspective. In some cases, even when she contemplates ways of making dance that in her mind would not work or would not be valuable, she was a sort of sage seeing the future of dance and what new and stubborn generations would try out - 10-20 years after the release of the book, some choreographers embodied exactly those ideas that according to her "would not work" and made them work.
I definitely agree with Humphrey that programs of dance and choreography in higher education establishments should teach a more formal dance theory course, which is not glued together with dance history classes. It is definitely a shock, that after all these years that contemporary dance has been regarded as a rather equal art form to other stage arts, it still does not have a comprehensive system of, or at least an attempt to systemize theory of choreography. Definitely, the one that Humphrey proposes might not correspond to the needs of the 21st-century new dance makers, but in some ways, it is much more up-to-date than some other approaches that are being pushed down nowadays. Mostly because it refers to what is happening (or was happening at the time of writing the book), not what should happen.
This book is definitely a must-read to all dance professionals - be it dancer, choreographer, critic, or especially theoretician.