For those people who have somehow managed to avoid it despite the fact that it's been linked all around the Internet for the past 10 years, this is a reminder that Bob Altemeyer's book The Authoritarians is available free in PDF form at the link.
If you want to take the RWA-scale questionnaire from the book, I have put up a convenient online version; this is completely private, all scoring is client-side and no results are stored or sent anywhere (not even to me).
(Edited 2018-10-04: update book link to new site)
