One of the biggest political questions across North America and Western Europe is how societies will adjust to increasing levels of ethnic, racial, and religious diversity. For many years, scholars have focused on the people who oppose diversity because their views are considered objectionable and in need of explanation. Ivarsflaten and Sniderman join a growing group of scholars who take a different approach and analyze the rest of the population: people inclined to support diversity. This is a crucial population segment because under the right conditions, they are the ones who will promote more tolerant and inclusive societies in the twenty-first century.

Ivarsflaten and Sniderman use an impressive range of original surveys—with an approach they call “sequential factorials”—to analyze the conditions under which Europeans are more likely to support the inclusion of Muslim minorities. “The sequential factorial” approach conducts many small experiments that replicate previous findings (increasing confidence in the results) and then extend the insights into new directions. Throughout the book, Ivarsflaten and Sniderman use 34 different experiments on over 21,000 survey respondents from Norway, the United Kingdom, the Netherlands, Denmark, the United States, Germany, France, and Sweden.

The main claim of the book is th