US President Donald Trump dismissed journalist Bob Woodward's bombshell book as a "joke" Monday, a day before readers get their first full look at his detailed account of a White House in disarray.

"Fear: Trump in the White House" hits US bookstores on Tuesday after a weeklong buildup, with published excerpts, leaks and interviews that portray Trump as dangerously erratic and uninformed. On the eve of its release, the president took to Twitter with a preemptive round of attacks, denouncing as fiction Woodward's reconstruction of scenes in which frustrated aides scramble to contain the mercurial president's reckless impulses.