Not many authors explain their reasons for writing books as bluntly as Neil Young does in "Waging Heavy Peace."

First of all there's the thing now known as the Keith Richards phenomenon: There turns out to be a large and lucrative market for memoirs from rock stars. In a two-page chapter called "Why This Book Exists" Young explains that his book will be a goose that lays a golden egg. He's writing it because it will earn him enough money to stay off the stage for a while, which he badly needs to do for mental and physical reasons.

"It all started when I broke my toe at the pool," he explains.

There may be a large part of the reading populace that has no interest in Young's broken toe, collection of funky old cars, obsession with toy trains, plaid shirts, favorite planks of wood or anything else. That's fine with him.

"I read up on this sort of thing, and the worst thing you can have is a book that is too long," he says, not remotely troubled that "Waging Heavy Peace" rambles on for 497 pages. "So if you are having trouble reading this, give it to someone else," he suggests. "End of chapter."

But this isn't a book to part with. It is as charismatically off the wall as Young's records, and the recent concert films so imaginatively directed by Jonathan Demme. And however privately calculating it may be, it seems completely free of guile.

"I have been with some of you for a real long time, and others of you don't have the foggiest notion what I am or what I stand for," Young writes. "I am possibly joining those legions myself." The fear of oncoming dementia, prompted by his father's medical history and mysterious cloudy matter on his own brain MRI exam, has lured Young, 66, into an altered state: sobriety.

"I am feeling very fashionable, even trendy, for having stopped smoking and drinking," he writes, but the change in him is serious. It seems to have interfered with his ability to make music while heightening a desire to get his story told right.

Among other books about Young are "Neil and Me," written by his father, Scott Young, and Jimmy McDonough's authorized biography "Shakey," which receives a nasty potshot from its subject. In doling out advice to "any old rocker who is out of cash and doesn't know what to do next," he suggests either doing it yourself or hiring a collaborator. "Just don't hire some sweaty hack who asks you questions for years and twists them into his own version of what is right or wrong," he says. "Try to avoid doing that."

But "Waging Heavy Peace" presents a much more playful, capricious portrait of the same tough, controlling person McDonough described. Young lives on his Broken Arrow ranch, a virtual fief full of friends and employees who help him with the pet projects that occupy much of his attention.

He loves to invent, build and tinker with things, to the point where "Waging Heavy Peace" is part infomercial: for the PureTone sound system, now called Pono, that he hopes can restore magic to recorded music, and for the Lincvolt, a hybrid with the body of a 1959 Continental that he hopes will someday be mass-manufactured and run on clean technology.

The personal stories about Young's children and their mothers, about friends and band mates lost to ill health and drugs, can be eerie. But "Waging Heavy Peace" has an affirmative spirit that is one of its most poignant qualities. The particular challenges that have faced Young and his wife, Pegi, in raising the son they call Ben Young, "our spastic, quadriplegic, nonverbal spiritual leader," are discussed openly but without pathos; for example, that Ben can now take nutrition only through a feeding tube is mentioned as a reason he will have to cut back on paddleboarding.

Young has faced so many serious health crises of his own - polio, epilepsy, surgery for a brain aneurysm that prompted him to quickly record one of his most haunting albums, "Prairie Wind," knowing that it might be his last - that he has learned not to accentuate the negative.

But as for mistakes he has made, he treats "Waging Heavy Peace" as a chance to acknowledge them. The book expresses great love for Zeke, the oldest of his three children, while acknowledging that Young fell in love with Zeke's mother, the actress Carrie Snodgress, when he saw her picture in a magazine. In hindsight he sees that romance - even though it had a lot to do with the beautiful "Harvest" - as a short-lived and sad chapter.

Susan Acevedo, the first of his two wives, sewed fashion-forward hippie patches onto the pair of his jeans seen on the back cover of "After the Gold Rush," using her hair as thread. One day he came home to find that Snodgress had taken the patchwork apart.

There are angry things that might be said about this episode. But Young keeps it Delphic, as he always has: "That was pretty numbing. I am not sure I am over that. Clothes make the man."