What I wanted for this post was an unobstructed version of the photo above, and I searched for it using the information on the back of the recently issued New York Review Books paperback where I discovered it:
Mak (Pavel Ivanov) and Elza Kruiger performing the tango, Moscow, 1913
But the book cover was the only version of the image I was able to locate and I like it so much that I am putting it up here even though I have no particular interest in the text (a collection of stories originally written in Hungarian during the second decade of the 20th century about a wandering seducer of the Don Juan or Casanova type).