President Trump is a book genre unto himself. There's “Understanding Trump,” by Newt Gingrich, whom Trump considered as a running mate; “Let Trump Be Trump,” by former Trump campaign aides Corey Lewandowski and David Bossie; “The Swamp,” by former Fox News Channel host Eric Bolling; and a forthcoming book by former White House press secretary Sean Spicer (working title: “The Briefing”).