Prince Charles was a “most likeable person,” President Gadhafi a “mad clown,” and Michael Jackson was “surprisingly shy.”

The private diaries of Ronald Reagan, which are about to be published for the first time, show a president who was worried about imminent Armageddon but who also fretted about how he would handle chopsticks in front of the Chinese.

The man who was credited with ending the Cold War shows that he was “lonesome” when his wife, Nancy, was away and refused to talk to their son, Ron Junior, after he hung up on him.

His carefully handwritten and succinct private musings, contained in five leather-bound books embossed with the presidential seal, span his eight years at the White House between 1981 and 1989.

Excerpts have been published in Vanity Fair magazine prior to a new book by Douglas Brinkley, a historian who was given exclusive access to the diaries.

They will reassure both Mr. Reagan’s supporters and his detractors, providing supporting evidence that he was both a dangerously simplistic buffoon or — alternatively — that, beneath the folksy exterior, lay a razor-sharp and highly principled mind. Complicated matters of state and world leaders are reduced to their essence, jostling for prominence in the late president’s mind with infinitely more mundane matters. “We have definite evidence of Nicaragua transferring hundreds of tons of arms from Cuba to El Salvador. p.m. ran a movie — Tribute — Jack Lemmon. He is truly a great performer,” he wrote in one entry.

An important visit to China kicks off with a state banquet but there is little talk of politics. “Here was our 1st go at a 12 course Chinese dinner,” the president wrote. “We heeded Dick Nixon’s advice & didn’t ask what things were we just swallowed them. There were a few items I managed to stir around on my plate & leave. We both did well with our chopsticks.”

Etiquette again reared its head during a visit by Prince Charles. “The ushers brought him tea, horror of horrors they served it our way with a tea bag in the cup,” Mr. Reagan wrote.

“It finally dawned on me that he was just holding the cup & then finally put it down on a table. I didn’t know what to do. Mike [Deaver, deputy chief of staff] escorted him back to the W.H. [White House] and apologized.” He said the Prince admitted: “I didn’t know what to do with it.”

Mr. Reagan’s homespun humor also finds its way into his take on world affairs. “Intelligence reports say Castro is very worried about me. I’m very worried that we can’t come up with something to justify his worrying,” he wrote in February 1981. Later, during disarmament talks, he is frustrated by the Soviet “paranoia” about being invaded. “What the h l [hell] have they got that anyone would want,” Mr. Reagan mused. The straight talking rhetoric that delighted fans and enraged critics is never far away. When the Iranians arrested an American journalist in Tehran, the president was “ready to kidnap the Khomeini.” At other times, he seems much less self-assured. His entry for June 7, 1981, reads: “Got word of Israeli bombing of Iraq — nuclear reactor. I swear I believe Armageddon is near.” His diaries confirm his admiration for Margaret Thatcher. On her visit to Washington in 1981, he wrote: “She is as firm as ever re the Soviets and for reduction of govt. Expressed regret that she tried to reduce govt spending a step at a time & was defeated in each attempt. Said she should have done it our way — an entire package — all or nothing.”

The only period in which he made daily diary entries was when he was shot on March 30, 1981. “I sat on the edge of the seat almost paralyzed by pain,” he wrote. “Then I began coughing blood…Getting shot hurts.”

Trouble with his children was a painful experience that Mr. Reagan, who died at 93 in June 2004, often chronicled in his diaries. One entry reads: “Ron called this evening all exercised because SS [Secret Service] agents had gone into their apartment while they were in California to fix an alarm on one of his windows. I tried to reason with him that this was a perfectly OK thing for them to do. I told him quite firmly not to talk to me that way and he hung up on me. Not a perfect day.”

Mr. Reagan also wrote frequently of his love for Nancy. A few weeks before he was shot he wrote: “Our wedding anniversary. 29 years of more happiness than any man could rightly deserve.”