William Shawcross, whose official biography of the Queen Mother was published by Macmillan in 2009, is to edit a selection of her letters for the same publisher.
Counting One's Blessings: The Selected Letters of Queen Elizabeth the Queen Mother will be published on 11th October.
Shawcross' biography included extracts from the Queen Mother's correspondence, which was hailed by the Sunday Times as "brimful of liveliness and irreverence, steeliness and sweetness". Now Shawcross has drawn on the wealth of material retained in the Royal Archives and at Glamis Castle to produce a full selection.
"A prolific correspondent from her earliest childhood before the First World War to the very end of her long life at the beginning of the 21st century, the letters offer readers a vivid insight into the real person behind the public face," Macmillan said.
Farrar, Straus and Giroux will publish simultaneously in the US, and HarperCollins in Canada.