Just what is the mystery? The National Union of Teachers proved most coy when taxed with rumours of a publication to celebrate this year's 125th anniversary.
Will there be such a book? "There may be," was the great union's gnomic reply, and not a word more. This is curious, because everyone already knows that the book is a history of the NUT since 1970, and that it has been written by the Guardian's Brussels correspondent and former education editor, Stephen Bates.
Once with the Daily Mail, Mr Bates has not shied away from criticising the NUT in his time. Some people - including Mr Bates - think the union's national executive is very brave to commission him. "It is generally supportive, but not necessarily entirely friendly to the NUT," he explained. "It's very difficult to write a history of the NUT over the past 25 years that says they have been completely successful."
The assorted finger-jabbers at next month's annual conference in Cardiff may take a different view. So it is jolly fortunate that Mr Bates' opus - tentatively titled Put to the Test - will not be ready in time for that spectacle.