It has to be at least ten years since I found a new (to me) publication of anything by Leonard Cline, so I was overjoyed to find that Cline had given a choice blurb for a book published by his own publisher, the Viking Press. The book is Roots by Eduardo Zamacois, translated from the Spanish (the book had appeared in 1927 as Las Raices). The translation is uncredited, but the UK edition of 1930 (and Viking's own renewal of copyright as a work-for-hire in 1957) gives the translator as Eliseo Vivas (1901-1991). (Interestingly, the translation does not appear in Hugh Mercer Cartler's Eliseo Vivas: An Annotated Bibliography (1981), where it would have figured as one of his earliest publications.)
Cline had died in January 1929, while the Zamacois book was not published until late October 1929, so Cline's comments probably date from sometime in 1928. Eduardo Zamacois (1873-1971) was born in Cuba, but left at the age of four, living in Belgium, France and Spain, until after the fall of Barcelona in early 1939, he fled to France, the U.S., and Mexico, before he settled finally in Argentina. He was a prolific writer, though little of his work has been translated into English.
The striking dust-wrapper illustration is by Paul Wenck (1892-1964), a German commercial artist who emigrated with his wife to the US in 1923. Wenck is known for dust-wrapper art in the late 1920s for publishers including the Viking Press, Horace Liveright, and Little, Brown--notably for the latter's 1929 All Quiet on the Western Front by Erich Maria Remarque. Cline's blurb is on the rear--the only text anywhere describing the contents of the book itself (the book has no introduction, and advertisements for other publications on the flaps).