Author Henry Bushkin is described as Carson’s lawyer and best friend, who worked for him for 18 years.
The gossipy, 304-page book claims Bushkin helped Carson “break into a posh Manhattan apartment to gather evidence of his wife’s infidelity.”
His former wife has in recent days denied reports of the old affair.
The book also claims that “more than once, Bushkin helped his client avoid entanglements with the mob.”
Carson, the book claims, also "prevented a drunken Dean Martin from appearing onstage" at President Ronald Reagan's inaugural ball.
According to Amazon.com, the new book debuted at No. 1 in the online store’s Humor & Entertainment and Biographies & Memoirs categories.
"He was notoriously inscrutable, as mercurial (and sometimes cruel) off-camera as he was charming and hilarious onstage," according to the book.
A previous version of the book was published under the title "A Hard Act to Follow."