When asked about writing or editing a book those who have done so generally reply “Don't do it”. This has not been our experience. When Nicki Dennis first approached one of us (Michael Walker) on behalf of the Royal Society of Chemistry to put together a book on DNA and food authenticity the reaction was – what a great idea, but I can't do this on my own. Two experts, Lucy Foster and Malcolm Burns, immediately sprang to mind and both readily agreed to participate. What followed was two years of hard work. But we can honestly say the experience has been one of exciting learning – from each other and from the subject matter experts who have generously contributed chapters. As a team of editors we appear to have complementary skills and networks so that the whole process has been one of collaborative enjoyment. The Royal Society of Chemistry team, Katie Morrey, Janet Freshwater and Robin Driscoll have been helpful and cooperative throughout. A particular mention must go to Dr Sandy Primrose. Sandy's vision is to bring the quality assurance rigour now commonplace in analytical chemistry to the younger discipline of molecular biology. This vision forms a core theme of the book and Sandy provided a guiding hand throughout, as well as contributing several chapters as a long-standing authority on food authenticity.

In terms of the expertise that we bring to this book, we all have food analysis in common. Dr Malcolm Burns trained as a plant molecular biologist at Birmingham University, gaining his PhD in quantitative trait loci mapping in Arabidopsis in 1997. Following a move to LGC Ltd after graduating, he has built his career in molecular biology, acting as the Principal Scientist for food authenticity testing, specialising in using and advising on advanced DNA approaches for food analysis at a national and international level.

Dr Lucy Foster [Institute of Food Safety and Technology (IFST) Fellow] trained as a food scientist, gaining her PhD in analytical and nutritional aspects of selenium deficiency in 1997. Following research roles at Unilever (Colworth) and the Institute of Food Research (Norwich) she joined the Ministry of Agriculture Fisheries and Food to work in food authenticity, and subsequently the Food Standards Agency to lead work in a variety of roles, including food additives and foodborne disease policy and running food science research and surveillance programmes. Following a move to the Department for the Environment, Food and Rural Affairs (Defra) in 2009 to lead agriculture and food chain research, she currently heads Defra's Agri-Food Chain Directorate's teams on food science, innovation, GM and genetic resources policy.

Dr Michael Walker is a Chartered Chemist and Fellow of both the IFST and the Royal Society of Chemistry, and holds the MChemA, the statutory qualification to act as a Public Analyst in the UK. He owns a thriving chemico-legal private practice, and is also Referee Analyst and Head of the Office of the Government Chemist in the UK National Measurement Laboratory hosted in LGC, a member of the European Academy of Allergy & Clinical Immunology, and a member of the IFST Scientific Committee. He was a subject matter expert to the UK ‘Elliott Review’ in the aftermath of the horse meat scandal and was a founder board member of the UK Food Standards Agency.

We have worked together over many years on food authenticity issues, but it was the horse meat incident in 2013 which threw us together in a unique way to deal with a variety of analytical challenges to meet the needs of government, industry and food law enforcers and consumers. This resulted in new ways of thinking about metrology, quantitative DNA analysis for food analysis, how this affects food law enforcement and gaps in understanding around some of the challenges using DNA applications. These gaps included ensuring fitness for purpose, harmonisation and standardisation of DNA methods. The incident also highlighted the need for greater awareness-raising of the existing and emerging analytical tools that are available to the wider community, as well as the potential for genomic approaches in the future as a tool for detecting food fraud. Discussions during a Government Chemist conference dinner in 2016 crystallised the concept for a book to address these issues.

This book provides, we trust, a valuable resource for learning more about the scope, application, benefits and pitfalls associated with DNA-based techniques in one comprehensive volume. It is unique in that it gathers a wide array of internationally recognised scientists, all experts in their fields of study, to provide authorship on topical and cutting-edge perspectives for food authenticity testing as well as providing insight into requirements for the future.

The book is aimed at those who wish to understand the fundamental principles of the application of the DNA-based approaches in the laboratory environment, those who are already practicing the techniques but wish to further refine their skill sets, and those who wish to learn more about the new and emerging techniques for food authenticity testing based on genomic approaches on the horizon. As such, we hope that the book will appeal to the food industry, official control laboratories, researchers, and students and experienced practitioners alike.

As editors we are indebted to all the chapter authors who have given up their valuable time and expertise to share their knowledge. They have worked with us enthusiastically to provide unparalleled breadth and depth of discussion. We would also like to thank colleagues in the Molecular Biology team at LGC and Defra's Food Science team, and Professor Sir Ian Boyd (Chief Scientific Advisor, Defra) for their contributions, support and encouragement

One of us (MB) also gratefully acknowledges funding from the UK Department for Business, Energy and Industrial Strategy (BEIS) as part of the Government Chemist Programme 2017–2020, and another (LF) acknowledges support from the Department for the Environment, Food and Rural affairs to provide the freedom to allow work on this book alongside our day jobs. Opinions expressed in the book remain entirely our own.

On a personal note, we would like to mention and thank our spouses (Sarah, Tony and Maria) and our families for their support and encouragement; they have graciously tolerated long hours over many months during which we were preoccupied working on the book.

Malcolm Burns, Lucy Foster and Michael Walker