Thomas Francis Dermot Pakenham, 8th Earl of Longford, is known simply as Thomas Pakenham. He is an Anglo-Irish historian and arborist who has written several prize-winning books on the diverse subjects of Victorian and post-Victorian British history and trees. He is the son of Frank Pakenham, 7th Earl of Longford, a Labour minister and human rights campaigner, and Elizabeth Longford. The well known English historian Antonia Fraser is his sister.

After graduating from Belvedere College and Magdalen College, Oxford, in 1955, Thomas Pakenham traveled to Ethiopia, a trip which is described in his first book The Mountains of Rasselas. On returning to Britain, he worked on the editorial staff of the Times Educational Supplement and later for ,i>The Sunday Telegraph and The Observer. He divides his time between London and County Westmeath, Ireland, where he is the chairman of the Irish Tree Society and honorary custodian of Tullynally Castle.

Thomas Pakenham does not use his title and did not use his courtesy title before succeeding his father. However, he has not disclaimed his British titles under the Peerage Act 1963, and the Irish peerages cannot be disclaimed as they are not covered by the Act. He is unable to sit in the House of Lords as a hereditary peer as his father had, due to the House of Lords Act 1999 (though his father was created a life peer in addition to his hereditary title in order to be able to retain his seat).

Books in order of publication:

The Year of Liberty: The History of the Great Irish Rebellion of 1798 – 1969

A Traveller’s Companion to Dublin – 1988

The Scramble for Africa: The White Man’s Conquest of the Dark Continent from 1876 to 1912 – 1991

The Boer War – 1992

Meetings with Remarkable Trees – 1997

The Mountains Of Rasselas: An Ethiopian Adventure – 1998

The Big House in Ireland – 2001

Remarkable Trees of the World -2002

The Remarkable Baobab – 2004

In Search of Remarkable Trees: On Safari in Southern Africa – 2007

The Company of Trees: A Year in a Lifetime’s Quest – 2015