Bush claims to have been the first president to really get tough on terrorism. “My decision” to invade Afghanistan “was a departure from America’s policies over the past two decades.” President Reagan withdrew American forces from Lebanon after Hezbollah bombed our Marine barracks there. President Clinton withdrew from Somalia when warlords shot down an American helicopter. He doesn’t mention his own father’s decision to stop the Persian Gulf war of 1991 at the Kuwait-Iraq border rather than proceed to Baghdad and take Saddam Hussein down. Bush concludes: “Terrorists had interpreted our lack of a serious response as a sign of weakness. . . . I was determined to change that impression.” So he made a serious response.

A pugnacious determination to be taken seriously is about half an inch below the surface of “Decision Points.” It’s poignant that even as a former two-term president, Bush should feel the need to strut the way he does. The book is full of maxims and advice. “I prided myself on my ability to make crisp and effective decisions,” Bush reveals. And here is his secret for hiring a White House staff:

“I started each personnel decision by defining the job description and the criteria for the ideal candidate. I directed a wide search and considered a diverse range of options. For major appointments, I interviewed candidates face to face. I used my time to gauge character and personality. I was looking for integrity, competence, selflessness and an ability to handle pressure. I always liked people with a sense of humor, a sign of modesty and self-awareness.”

“Timeliness was important” to make sure an organization does not get sloppy, Bush reveals. And: “I learn best by asking questions. In some cases, I probe to understand a complex issue. Other times, I deploy questions as a way to test my briefers’ knowledge.” Like every president, Bush believed he could bring peace to the Middle East, and he even had a notion about how to do it: “My vision is two states, living side by side in peace and security.” What a good idea! So that’s settled.

Speaking of a sense of humor and the Middle East, when Bush called for a new Palestinian leadership, Barbara Bush the elder (“Mother,” he invariably calls her) rang up to say, “How’s the first Jewish president doing?” Maybe I’m deficient in humor, but I don’t see why this is funny, as her son clearly believes it to be. I might even find it alarming if Bush didn’t crowd this book with ­maybe-you-had-to-be-there witticisms. After his first meeting with Prime Minister Tony Blair, “a British reporter asked what we had in common. I quipped, ‘We both use Colgate toothpaste.’” Huh?

Wanna hear more? Sure you do. So 41 (George the elder) is at the Mayo Clinic, recovering from hip surgery. He says to the nurse, “Are my testicles black?” Pause for reaction. “I said, ‘Are my test results back?’ ” The son reports, “His medical team roared with laughter.” O.K., O.K., one more: “We had a saying in West Texas: ‘Last night he thought he was a 10, when in fact he was an ass.’ ”

Whatever that description means, exactly, Bush applies it to himself until the day after a 40th-birthday celebration, when he stopped drinking with the help of God, who spoke to him while he was out jogging. (I make light, but this part of his story is actually fascinating, gutsy and very well told.) Thirteen years later, after he had made a quick fortune buying and selling a baseball team and then had been elected governor of Texas, God told him to run for president. “I felt a calling to run,” Bush writes. “I was concerned about the future of the country, and I had a clear vision of where to lead it. I wanted to cut taxes, raise standards in public schools, reform Social Security.” Bush never indicates where this laundry list of views came from. He had no political views he deems worthy of mention before the age of 40, but a few years later he has a complete set. You do have to wonder how deep they run.

Doubts arise about the depth of Bush’s principles in part because he so often clung to them even as he violated them. A typical Bush mind change goes like this: (1) I have always believed deeply that X. But (2) in this case X would cause vast human suffering or higher taxes or some other terrible tragedy that I couldn’t, as president, allow. Therefore (3) I will abandon X on this occasion. But (4) I still believe deeply that X.