The intellectual origins of this book are explained in chapter 1, but, as with many books, there is a parallel story about its conception. It began in 2007, when three of the authors (MW, ML and PB) examined the Farm Management Survey archive at Exeter and rapidly concluded that it was potentially of great historical value. Since we had all been interested, from different perspectives, in the changes that had been occurring in agriculture throughout our working lives, it is tempting to speculate on whether we would ever have co-operated on researching the topic together in the absence of the archive; what we know, however, is that the potential threat to its existence, brought about by the relocation of the Centre for Rural Policy Research from one Exeter University building to another, precipitated a joint decision to explore the archive further. We obtained a British Academy grant in 2007–8 to employ a research assistant, Dr Helen Blackman, who catalogued its contents. The following year, together with another colleague (DH), we obtained an ESRC grant to fund work on the field books, looking specifically at the evidence for technical change and the explanatory variables associated with it. The grant enabled one of us (PB) to devote most of his time to the project and also to employ Dr Allan Butler as a research fellow.

It is this decision to concentrate on what the archive, together with other sources, can reveal about technical change in agriculture that determines the range of dates in the title of the book. As we explain in the text, the period between the late 1930s and 1985 was one in which UK agricultural policy more or less consistently promoted increasing output. Before and after those dates, the policy message was less clear, so additional variables played a part in farmers’ decision-making on investment and the adoption of new technology. There is an interesting book to be written about changes in UK agriculture after 1985, but it is not this book.

Inevitably, we have accumulated numerous debts of gratitude in the course of our research and writing. Without Helen Blackman’s rapid and efficient cataloguing work, we would not have been successful in obtaining the ESRC grant, and she later went on, with Katie Garvey, to help with the analysis of the field books.