High Park, at Blenheim in Oxfordshire UK, is a SSSI of great significance for its numerous ancient oaks and the organisms associated with these trees. This book gives a detailed, lavishly illustrated and thoroughly researched description of the biodiversity and natural history of what is by several measures the most significant site for ancient oaks in Europe. It draws together the expertise of more 60 specialists, and reports on the results of in-depth surveys of High Park. Chapters cover different groups, including: flora (including bryophytes), fungi, lichens, molluscs, arachnids, flies, hymenoptera, butterflies, moths, beetles – with a special focus on saproxylic species, bugs, reptiles and amphibians, birds and mammals. Despite their undoubted importance, very few sites with ancient oaks in England, the most important European country for these magnificent trees, have seen a comprehensive published account, adding to the value of this study. Several of the contributing authors describe their survey techniques in some detail, some of which are not widely known. Records are analysed in the various chapters and often compared with data from other similar sites. Overall, the book gives encouraging evidence of the great biodiversity still to be found in England, and should help to stimulate similar efforts to uncover the biodiversity and describe the natural history of ancient parkland and woodland, so that conservation of these sites can be based on firm scientific data.