I ask the question with a certain amount of residual love: Is William Shatner the guy you want life advice from?

He was cordially disliked by virtually all his “Star Trek” castmates, some of whom he is still feuding with half a century later. He trails a couple of brutal divorces in his wake, and by his own admission, has had very few friends over his 87-year-old life. The man he describes as his best friend — Leonard Nimoy — refused to speak to him during the last five years of his life for reasons Shatner has yet to divine.

“Live Long and . . .,” by William Shatner and David Fisher (Thomas Dunne)

As for career advice . . . well, Shatner continues to identify as a recording artist despite decades of evidence to the contrary. He has starred in the only full-length movie ever made in Esperanto. He has declared that an alien saved him after a motorcycle accident in the desert. He has negotiated a face-saving transformation from inadvertent bad acting (“Star Trek,” “T.J. Hooker”) to self-parodic bad acting (“Boston Legal”) without any apparent understanding of what he has done.

The good news, I suppose, is that even William Shatner doesn’t think he’s qualified to give advice. “I am not a font of wisdom,” he confesses in his new book “Live Long and . . .,” written with David Fisher. “I’m the guy who saved the Starship Enterprise for seventy-nine weeks and ended up kissing James Spader on a patio.” He likewise believes that “to try to tell anyone else how to live their life is the ultimate in hubris. There is no one way, or right way, to do anything.”

And if you think that will stop him from telling anyone else how to live their life, you haven’t reckoned with the enduring template of celebrity self-help. Consider that, over the past year, entertainment figures such as Jessica Alba, Kevin Hart, Vivica A. Fox, Suzanne Somers and Tyra Banks, have weighed in on how to make ourselves smarter, healthier, stronger, sexier, funnier — better. Maybe the only question that remains to be answered is why we listen. Do we really think that getting yourself on TMZ confers its own diploma? That good teeth translate to good character? That with great social-media penetration comes great responsibility?

For now, there is the evidence of Shatner, who tosses out bromides like beads at Mardi Gras. “Make the best of every decision and never look back on it. . . . We can’t do anything about the past and we don’t know what the future will bring, so there is nothing we can do but live in the moment. . . . Love can be addictive. . . . Emotions run wild! . . . We think we know so much, but we know so little.” Leavening the banality are kinda-tedious anecdotes about paramotoring and driving through a blizzard and, okay, less tedious stories about soiling himself during a one-man show on Broadway and being attacked by a monk seal while on vacation.

And because this is Shatner, a certain amount of Planet Crazy does seep through. This may come in the form of dreadful song lyrics: “Where does time go:/I finish the dishes, I go to the store; before I know it, time is no more.” Or vainglorious poses: “There are people who ask, ‘How could you have done that? Don’t you know your life is at stake?’ And my response was always, ‘How could I have not done it? My life was at stake.’ ” Or alternative history: “Why couldn’t Joan of Arc have said, ‘I have a split personality; I am bipolar,’ and after her jailers left said, ‘I am not bipolar. I only said that to live’?” And, here and there, the kind of sentence engineered for spit takes: “One of the earliest relationships I formed was with a prostitute, who became my friend.”

It may be that the key to enjoying any celebrity self-help tome is to find the crevices between messages intended and unintended. By this standard, the most authentic moment in “Live Long and . . . ” is when Shatner crows that he has more than 2.5 million followers on Twitter and another 2 million on Facebook. The least authentic, surely, is when he claims that he is “completely comfortable” with his life. Those words cannot apply to a man who has been working nonstop since he was 6 years old, who lives in mortal fear of the “blank pages in my datebook,” who, in recent months, has sparred for no clear reason with the star of “Star Trek: Discovery” and alienated progressive Trekkies with alt-right triggers like “misandry” and “snowflake,” and who, in titling his book has co-opted the very Vulcan salute patented by his dead friend Leonard.

Maybe celebrities need just as much help as the rest of us.

Louis Bayard is a novelist and reviewer. His upcoming book is “Courting Mr. Lincoln.”

What I Learned Along the Way

Thomas Dunne/St. Martin’s. 224 pp. $26.99