Isadora Duncan "My Life" online

  Depending on how the searching would  come along, the page would be updated .
French edition:

English:
  Internet Archive or Project Gutenberg
Russian: The Russian translation is freely  available everywhere .
Chinese edition:(preview only, those who knows where to find the whole book in chinese, legaly online,please,share a link)

Japanese(preview only):
  
Marathi (India): Digital Library of India or Internet Archive
Spanish:Biblioteka Digital Hispanica

The Dance of The Future, New York, The Forest press, c. 1909. With introduction by Mary Fanton Roberts and samples of concert programs.

The Dance of the Future in Polish language. Izadora Duncan "Taniec przyszłości", WARSZAWA 1905. Polona library

Taniec przyszłości odczyt Izadory Duncan

"Isadora Duncan's Russian days and her last years in France" by Irma Duncan, Allan Ross McDougall. Victor Gollancz LTD,London,1929.

This is so good when information about Isadora Duncan become available to public time after time. I hope you would find this link usefull.

Arnold Genthe "The Book of the dance". USA,Boston,1920.

Just sharing for those,who haven't seen this book yet.

"The dance of the future" full book,both in English and German. Germany,Leipzig,1903.