This is an interesting study of two unbalanced personalities, Ernest Hemingway and his third wife, Martha Gellhorn, before and during their trip to the Far East from January to May of 1941. Hemingway was a very heavy drinker, at times abusive but capable of great charm, and Gellhorn, a true limousine liberal stamping out injustice and helping the poor, but totally unable to allow herself to come into contact with them.
But do not be deceived. Hemingway did not "spy" on anyone, there was no "mission", and the US was not yet in World War II. The basis for the sub-title was that Hemingway reported separately (from his published reports) to Secretary of the Treasury Henry Morgenthal and Harry Dexter White. They recognized that Hemingway and Gellhorn might write pap and propaganda for the public (sounds like contemporary media reporters) but wanted to obtain a balanced assessment of the readiness of the Far East in case of a Japanese attack, and most particularly China which was gobbling up vast sums of US aid.
The stories of Hemingway's drinking bouts and Gellhorn's obsession with cleanliness became wearisome. However, the depiction of China as a poor, filth-ridden country with a fascist government was nonpareil. The corrupt Chiang was more interested in fighting the communists than the Japanese, and the vast majority of US aid was not going into fighting Japanese aggression. The author makes this very clear, but there is little followup explaining why FDR continued his ruinous policies with respect to China until Japan was defeated literally without or in spite of Chinese help.
Some of the author's errors will be jarring to an historian. For whatever reason, he seems to only very reluctantly concede that Harry Dexter White was a spy, and he leaves the case against the Canadian born Laughlin Currie (like the author) somewhat in doubt. This is incomprehensible for a writer in 2004. The publication of the Venona material in 1995 established for all time that White was a high-level Soviet agent who did almost irreparable harm to the US while leading the American delegation in setting up the IMF (one of the KGB's finest hours), and Currie was part of the Silvermaster ring under the code name "Page." One of his major coups was reporting to Stalin that FDR was willing to let the Soviet Union keep the half of Poland they conquered in 1939, and that he would pressure the London Polish exile government to make further concessions. (See Haynes & Klehr, "Venona" for details.) Following that, the betrayal of the Polish exiles and their army was a foregone conclusion. At any rate, these were the birds with whom Hemingway was flying.
A small point is the editing. For example, author Moreira states that Hemingway committed suicide in 1961 and Gellhorn followed 27 years later with her own suicide in 1998. The author and his editors need a lesson in math.
All in all this book is an interesting read concerning life in China and the British colonies in the Far East in early 1941. Hemingway and Gellhorn are flawed and complex characters worth in-depth studies, but one needs a strong stomach and substantial personal interest to deal with their idiosyncrasies. They fit the CBI (China-Burma-India) theater well, particularly the other name used for the CBI theater, "Constant Bickering Inside."