NEW YORK — Sales are soaring for the upcoming book by incendiary right-wing commentator Milo Yiannopoulos but details of his promotional tour – assuming there is one – are a mystery for now.

A spokeswoman for Threshold Editions, the conservative imprint at Simon & Schuster, declined comment Thursday when asked where Yiannopoulos was expected to appear.

Publishers would usually be anxious to share details about a book just a few weeks from publication, March 14, and in high demand from the public. “Dangerous” was No. 1 on Amazon.com as of Thursday.

But the controversy that has driven pre-orders for “Dangerous” has also made promotion unusually complicated. The 32-year-old Breitbart editor, born in Greece and raised in England, is a walking challenge to free speech principles.

A vocal supporter of President Donald Trump, Yiannopoulos has made vicious comments about Muslims, women and others, and on his website offers such products as “Feminism is Cancer” T-shirts and “Fat Shaming Works” hoodies. His harassment campaign last summer against “Ghostbusters” star Leslie Jones led to his banishment from Twitter.

On Wednesday, California, Berkeley canceled a scheduled talk after violent protests broke out.

– From news service reports