There is an ongoing debate among National-Socialists and White Nationalists over which English language translation of Mein Kampf is the best.
NS Bibliophile believes that the Ralph Manheim translation published by Houghton Mifflin, while not perfect, is superior to all others. Despite his undisguised hostility to Adolf Hitler and the NS worldview, Manheim's translation is the most accurate and best captures the spirit of Hitler's message.
However, there are some people who prefer the James Murphy translation, first published by the British publishing house of Hurst and Blackett in 1939. Sadly, this preference is not based on the quality of the translation, but rather on the dishonest claim made by the publisher that the Murphy translation is the "official version" and "authorized" by Hitler himself. But that is not true.
Here is a short version of the true story: In 1936, the German government contracted with Murphey to do a translation of Mein Kampf, and Murphy made an initial rough draft. It contains numerous errors, and the prose is stilted and awkward. However, Murphy was ill and did not have the energy to complete the project. His rough draft was obtained by Hurst and Blackett, which they published, without corrections or modification, in 1939 as the "authorized" English edition. But neither the German government nor Hitler himself ever approved Murphey's initial draft.
But it gets worse: because he was ill, Murphy hired one Greta Lorke an assistant translator to help him out. Unbeknownst to him, Lorke was an operative of the "Red Orchestra" (Rote Kapelle, auf deutsch), the notorious Communist espionage and sabotage ring run by the Soviet Union. She saw working on the Mein Kampf translation as a perfect cover identity that allowed her to participate in Red Orchestra activities without drawing suspicion to herself. Additionally, she saw the assignment as an opportunity to discredit Hitlerism by fiddling with the passages that she translated.
An account (sympathetic, of course!) of Lorke's involvement in the Murphy translation may be found on pages 110 - 111 of the book Red Orchestra: The Story of the Berlin Underground and the Circle of Friends Who Resisted Hitler by Anne Nelson, Random House, NY, 2009.
A fuller examinaton into Lorke's role (including the insertion of deliberately erroneous material) appears in a harder-to-find earlier volume, Hitler's Mein Kampf in Britain and America by James J. Barnes and Patience P. Barnes, Cambridge University Press, NY, 1980.
To summarize: (1) the James Murphy translation of Mein Kampf published by Hurst and Blackett was an uncorrected rough draft made by a sick man; (2) it was NOT authorized or approved by either Hitler or the German government; and (3) parts of the translation were done by the Soviet spy and saboteur Greta Lorke, who was pursuing her own anti-NS ideological agenda.
Once again, NS Bibliophile recommends the Manheim translation -- or better yet, the German original!