First edition, first printing of the authors’ first book. Of all the first books by American golden age crime writers (Stout, Carr, Gardner, Chandler, Hammett, etc.), this has been, in common experience, the scarcest.
We have handled just one other copy in a slightly defective dust jacket. This example is the best we know. A Haycraft Queen Cornerstone.
All our catalogued works on detective fiction can be viewed online here.