To Renew America, the 260-page collage of Mr Gingrich's thoughts on America's plight and his nostrums for its salvation, has shot to the top of the non-fiction lists in the fortnight it has been on sale here. This weekend the book, which appears in Britain today, was number one in both the Washington Post and Wall Street Journal charts, and rising fast in the New York Times, whose figures include the first few days of July.
The initial print run ordered by HarperCollins, the publishing house owned by Mr Murdoch, was 600,000. If that sells out, and assuming a writer's royalty of 15 per cent of the $24 cover price, the Speaker stands to net about $2m (pounds 1.3m).
His chances of doing so will not have been hurt by a gushing review in the Journal by Baroness Thatcher, here at least still a venerated earth mother for conservative radicals. Reading the book, she writes, is "a breath of fresh air" after the "stale half-truths and platitudes" so often heard in western politics today. And, she adds, "the best [of Gingrich] is, I suspect, yet to come".
Even so Mr Gingrich, who will make a 23-city national promotional tour during the August congressional recess, will do well to match the $4.5m (pounds 3m) he would have received under his original contract with HarperCollins.
Whether that controversial deal was a Murdoch sweetener designed to hasten Republican legislation favourable to the media magnate will be the topic of the bipartisan House committee. Mr Gingrich is scheduled to testify on 27 July.
Devoted students of the Speaker will find little new in To Renew America, beyond the glib assertions which stud it from start to finish. A sample: ''When more people below 30 believe in UFOs than believe their pensions will be waiting for them when they retire, you know we are ready for a change in course.''