There has long been a myth that Franklin D. Roosevelt in effect ignored the Jews of Europe in 1933-45 when in fact he might well have saved most of them. Older books that treat with the topic have developed this myth to the point that it has become a "popular fact," along with the one about knowing in advance about Pearl Harbor, or giving Eastern Europe away to Stalin without a fight. FDR was hardly perfect and had some serious failures mixed with his monumental successes; but the "popular facts" mentioned above are blatant rubbish, and in the case of the salvation of the Jews, Robert N. Rosen has made a major contribution to the debunking process. (Fortunately, newer general biographies of FDR - e.g. those by Jean Arthur Smith and Conrad Black (both very much worth reading) - are no longer repeating these shabby legends, but they persist nonetheless.)
Rosen's is primarily a scholarly approach: Citations abound and the references used comprise a formidable list indeed. And on that basis alone this is a magnificent first encounter with its topic, especially for one who has the interest and resources to pursue the matter further via the bibliographic material. Though not particularly even-handed in its treatment, Rosen's book nevertheless is very clear when it comes to what Roosevelt tried to do, what he in fact achieved and what he didn't, and in each case why things went as they did. And Rosen is not above faulting FDR in matters where Rosen feels there is fault, though he hardly belabors these elements (as he does in a few cases of the opposite assessment).
But the book is not overly well written for general reading; the style is abrupt, sometimes fairly mechanical, occasionally repetitious, and too often a bit awkward when viewed primarily from a literary vantage. In short, Rosen is a brilliant scholar and a magnificent researcher; he is not however a terribly good writer. (Lord Black has somewhat the same problem in his monumental biography, but not even remotely on the same level.)
In addition there are a few proof-reading lapses that it would be well to fix, lest readers who know better confuse errors of minutiae with errors of real substance. As examples, Governor Herbert Lehman was not "Herman" (p.21); Vice-President John Nance Garner was not "James" (p.135); and Robert H. Jackson was not one of the judges at the Nuremberg Tribunal, he was the chief prosecutor (p.206).
In summary, Rosen's book is a superb treatment of its topic in terms of depth of fact and support for the material, and in solidly-researched debunking of persistent myths that really ought never to have been allowed to grow in the first place. Rosen's work could, however, do with a bit of touch-up in places, and perhaps a bit of help with the mechanics of narrative would have made it a smoother read for the non-scholar.