When you work in a rapidly developing field like genetic genealogy, books go out of date. This book was originally published in 2019 and I read & reviewed it then. A new edition has been published this year and it is substantially meatier than its progenitor. The same group of authors worked on the revised text, which I understand was finalised before Christmas in 2024. The nature of this type of book is that some things are already a little out of date. In the chapter on mitochondrial DNA, it talks about a new version of the Mitotree coming soon, and we do indeed have that now. Similarly, some of the graphics for What are the Odds tools from DNAPainter show the older version with numbers rather than the WATO+ with percentages.
The book breaks down the principles of the 3 DNA tests with pratical examples and case studies. I felt the chapters written by a single individual were more coherent than those written by a group. As someone who uses DNA testing in her work, there were still things for me to learn, but I do think the Y-DNA chapters may be too scientific and dry in tone for the novice tester. The ethics chapter (which was good before) is an important read, as is the related discussion in the chapter on ancient DNA, which is new to this edition. The glossary has been expanded and revised. I know traditionally we put those at the back of books but I do think this one should be upfront. Read it first, especially if this is a new topic for you.
Overall, there was a bit of repetition between chapters which is not surprising when you know they were written by different people, but perhaps more editorial work could have ironed this out. A complaint I had last time, and about all Pen & Sword books, is the images being in black and white. In one chapter, the text about a particular diagram actually references colours which the reader cannot see. I’d pay more for a book with colour images. I don’t know if the ebook editions offer this but perhaps if someone reads one that way, they could let me know.
It’s not bed time reading but definitely worth the small investment and something I think you would refer to again. If you’re reading this review after 2025, check in case there’s something more recent.