Ben Zuckerman, the president of the board of the anti-immigrant Californians for Population Stabilization (CAPS) co-edited a book with well-known white nationalist Michael Hart. The book, Extraterrestrials: Where Are They?, examines the plausibility of aliens existing and was first published in 1982 and again in 1995, but a 2015 email exchange obtained by the Southern Poverty Law Center indicates that Zuckerman cared little about Hart’s openly racist beliefs.