Aides said Mr. Bush agreed to speak so freely with Mr. Draper only after years of lobbying, in which Mr. Draper said he finally convinced Mr. Bush and his aides that he was writing about him as “a consequential president” for history, not for the latest news cycle. And aides said they saw the book as the first effort to write about Mr. Bush in the context of nearly his entire presidency.

The lobbying culminated at a meeting at the White House last August in which Mr. Bush grilled Mr. Draper on why he should cooperate with him of all the authors likely to come knocking. Mr. Draper replied that his book could provide “the raw material” for others after him, a point Mr. Bush apparently came to embrace.

Mr. Draper, a Texan like Mr. Bush and a former writer for Texas Monthly, spent hours interviewing Mr. Bush and his close circle of aides in 1998, when he wrote an early, defining article on Mr. Bush’s budding presidential candidacy for GQ magazine.

Mr. Draper’s family also has a history with Mr. Bush’s. Mr. Bush’s father in 1982 was an honorary pallbearer at the funeral of Mr. Draper’s grandfather, Leon Jaworski, a special prosecutor in the Watergate scandal.

As Mr. Draper described it, Mr. Bush began the interview process over lunch last Dec. 12, in a week when he suddenly had free time because his highly anticipated announcement of a new Iraq strategy had been postponed.

Sitting in an anteroom of the Oval Office, he eschewed the more formal White House menu for comfort food — a low-fat hotdog and ice cream — and bitingly told an aide who peeked in on the session that his time with Mr. Draper was “worthless anyway.”

But as Mr. Draper described it, and as the transcripts show, Mr. Bush warmed up considerably over the intervening interviews, chewing on an unlit cigar, jubilantly swatting at flies between making solemn points, propping his feet up on a table or stopping him at points to say emphatically, “I want you to get this” or “I want this damn book to be right.”