The book, titled “Rage” and a follow-up to 2018’s “Fear”, is due out on September 15.
Trump and Kim have met three times, beginning with their landmark summit in Singapore in June 2018, but little progress has been made on efforts to denuclearize the North.
A few months after Singapore, Trump told a rally of his supporters that the two men had fallen in love.
“No, really, he wrote me beautiful letters, and they’re great letters. We fell in love,” he said.
Negotiations have been deadlocked since the collapse of a second summit in Hanoi in February last year.
But even with diplomacy at a standstill, Trump has frequently boasted of receiving “very beautiful” and “excellent” letters from Kim.