Fifteen years ago, when I started the research that led to this book, diversity was an idea that was just becoming popular in business circles. I was excited to discover its deep roots in higher education, where diversity policies were almost universally embraced, and in constitutional law. But the origins of the diversity principle were little discussed. I hoped that my discoveries would help educators and business leaders to trade ideas and learn from each other as we explored the emerging science of diversity.

When I signed a contract with Yale University Press to pull my research into a book, the business case for diversity and diversity were well established. I then hoped my book would help students, educators, business leaders, and policy makers appreciate diversity’s deep roots, and how two hundred years of profound thinkers had given us this gift.

But by the time the book was released we were in a full fledged retreat born of a political war against diversity aimed at universities, scientists, businesses, law firms, and medicine. I had to add a postscript, which can be found on the book’s website, to bring the book from January 21, 2025 to January 1, 2026.