Oliver Rackham OBE, FBA (17 October 1939 – 12 February 2015) was an academic at the University of Cambridge who studied the ecology, management and development of the British countryside, especially trees, woodlands and wood pasture.

He kept a series of notebooks, which he began during his youth and continued until his death, in which he recorded observations on plants seen in his home surroundings and on his travels, in addition to information about the weather and his college duties.

[1] Arising from his research on Hayley Wood in Cambridgeshire, he developed the concept of ancient woodland, rich in plant diversity and managed through traditional practices.

His 1980 book Ancient Woodland, its History, Vegetation and Uses in England led to the recognition of such areas by the Forestry Commission and in planning legislation.

In 1986 he published The History of the Countryside, regarded as his greatest achievement and described as "a magisterial 400-page account of the British landscape from prehistory to the present day, with chapters on aspects ranging from woodland and hedgerows to marshes and the sea."