This volume publishes facsimiles of Repton's Red Books for neighbouring properties in the Mimram Valley of East Hertfordshire. Commissioned for the 5^th Earl Cowper and his cousin Henry Cooper, the Red Books are now owned by Hertfordshire Record Office, which has taken the opportunity to increase access to these valuable but fragile documents. This volume does so attractively, in the oblong octavo format of the Red Books, with clearly photographed illustrations and text. If the paper appears in a darker shade than the originals, this is perhaps to ensure that Repton's penmanship is legible. The introduction might have been more informative given the available archives on the commissions and the extensive published literature on the eighteenth-century gentry, landscape, parks and gardens, particularly in Hertfordshire.

Repton barely mentioned these commissions in his published works, perhaps because the major feature of his plan for Panshanger, a palatial new mansion designed by his son, was never built or, rather, was built to the design of another architect. Panshanger's significance grew with the publication of Dorothy Stroud's 1961 book on Repton which drew on Hugh Prince's pioneering 1959 archival study of the place's parkland design and estate management. After the sale of the house in 1953 and the first deposit of the family archive to the county record office, the park was divided up into lots and quarried for sand and gravel. There is a rich literature on Hertfordshire landscape history including a chapter in Sarah Spooner's 2010 doctoral thesis from the University of East Anglia, ‘The Diversity of Designed Landscapes: A Regional Approach c.1660–1830’. This makes it clear that these Red Books of designs and their accompanying manuscript sources are highly significant for an understanding of Repton's art and of the role of designed parks in larger landscape histories.

The Earls Cowper enjoyed spectacularly rising fortunes in the eighteenth century and dealt powerfully in an intricate local land market, sometimes paying well over the going price for modest properties, as well as pushing through enclosures and road diversions, to effectively own and control most of the Mimram Valley from Welwyn to Hertford. Their power in the land came to rival that of their peers in the county, the Earls of Essex at Cassiobury and the Marquis of Salisbury at Hatfield, and they were able to lord it over the bankers, merchants, nabobs and East India Men who sought a stake in the county. The family were not resident for much of this period. The 3^rd Earl preferred living in Venice where he amassed a large art collection and the 4^th died young. The 5^th Earl, Peter Leopold Louis Francis Nassau Clavering-Cowper, decided to call in Repton soon after succeeding to the title in 1799 in order to stamp the presence of the family in the county. Repton, in his professional way, was on a parallel path to landscape domination. The Cowper commissions are part of the dense cluster of commissions on the Hertfordshire/Essex border within convenient reach of his home at Hare Street. They came at a time when he had already undertaken well over a hundred Red Books and was greatly extending his geographical range. He was keen to raise the theoretical as well as the architectural status of his art in a major published work, in addition to asserting the superiority of a visiting consultant over the locally based land surveyors, builders, nurserymen and owners who undertook so much modest ornamental improvement.

As Repton observed, what distinguished the Cowper's noble domain was its command of lowland river scenery, a highly fashionable subject of landscape prints and paintings of the time. The valley was to be viewed from a picture gallery in the new mansion housing the family's art collection. The young 5^th Earl appears to be shown in the Red Book drawing the valley, supervised by Repton himself, who always saw his skill as a watercolourist as a way of mixing with the best circles. Cowper's control of the river valley allowed Repton to show off his scientific side, in his hydrological engineering techniques and his interest in the theory of optics. A ‘Digression’, an extract reproduced from an earlier Red Book for Purley, recalls a walk along the Thames to show the field of vision of an east-west valley at contrasting times of day. In the morning the ‘natural’ features of water, trees and meadows are highlighted whereas the evening shows ‘artificial’ features of buildings, boats, paths, villages and towns.

The Red Book for Tewin Water along the valley is focussed on drainage rather than irrigation and the breaching of formally designed standing water to restore ‘the rattling trout stream of Hertfordshire, fretting over its bed of gravel’. At the same time as celebrating county topography, Repton was keen to condemn the ‘local attachment’ of former owners who allowed the public road to cross the water and go close to the windows, ‘leaving the house on a kind of peninsula surrounded by carts, wagons, gypsies, poachers &c &c’. Rather less of Repton's plan for Tewin Water seems to have been realised than the introduction of this book suggests. The park, if not the mansion, of Panshanger was made according to Repton's plan. Pevsner noted in 1953 that it was ‘one of Repton's most perfect schemes’ and it is still discernible in the remnants left by subsequent development.