The author described Trump as "far and away the most difficult" new president to brief.
Trump was, like Nixon, "suspicious and insecure about the intelligence process," the book said.
Briefing Donald Trump as he prepared to enter the White House was more difficult than briefing any other incoming president, a book published by the CIA said.
The publication, "Getting to Know the President," by John L. Helgerson, a former intelligence officer, charted different presidents' interactions with intelligence agencies.
In it, Helgerson wrote: "For the Intelligence Community, the Trump transition was far and away the most difficult in its historical experience with briefing new presidents.".
Helgerson wrote that the only comparable experience to Trump's transition was that of President Richard Nixon.
"Trump was like Nixon, suspicious and insecure about the intelligence process, but unlike Nixon in the way he reacted," Helgerson wrote. »
