Speaking of human mortality, there are far more Mr. Spock fans alive now who first encountered the most memorable character from “Star Trek” in syndication than who viewed him on the original black-and-white television series that debuted 50 years ago.

LEONARD, Canadian co-star William Shatner’s heartfelt biography of a fellow actor who evolved from professional competitor, to personal friend, to lasting enigma, memorably captures the essence of an individual who could be as inscrutable in real life as his “Star Trek” persona on both the big and small screens of the entertainment industry. In fact, as Shatner suggests in a number of contexts throughout the book, the late Leonard Nimoy and Spock became a fan industry in their own right, both willingly and unwillingly.

While the seeming acceleration of later life can evoke somber feelings for those of us who tuned in for the show’s tentative launch back in 1966 and were around to mourn Nimoy’s passing in February 2015, I’ve come to appreciate how fully and irrevocably the entire original cast embraced the iconic status their roles acquired over time. In fact, their fan base kept growing for decades after the 70-odd “classic” episodes had left the air and were supplanted by a remarkable variety of spin-off series, feature films, animations, novels, comics, licensed products and the like.

"I found myself absorbing contrasting and similar slices of two fascinating lives, nodding in agreement one moment, wincing in exasperation the next, at times even feeling the lead weight of shared griefs and unresolved misunderstandings."

Balancing the mixed blessings of popular success and its very public instant recognition factor with the need to protect, preserve and grow one’s inner off-stage life clearly impacted Nimoy and Shatner to a far greater degree than the rest of the original Enterprise bridge crew. So with LEONARD --- to borrow a much-loved Spockian turn of phrase --- it was only “logical” that a cast companion who’d also struggled for decades to make a decent living as an actor, and then suddenly found success on an unlikely show about a galaxy-hopping spaceship, should be the one to give the eulogy.

As the book unfolds, each chapter affirms that the most interesting relationships never conveniently track along an orderly continuum of ups and downs, tensions and relaxations, or intimacy and distance. But the sometimes-volatile interactions of Shatner and Nimoy add extra ingredients of incongruity, discontinuity, contradiction, even confusion. It simply wasn’t one of those ideal fraternal bondings played out the way a television drama would demand.

Instead, to the credit of Shatner and his seasoned co-writer David Fisher, LEONARD reads as an honest, affectionate, even at times vulnerable reminiscence that tells as much about the biographer as his subject. The reader is drawn into a flow of deep feeling and emotion rarely expressed by the real-life Nimoy or his alter-ego, as Shatner, whose career as Captain James T. Kirk aptly equipped him to boldly explore inner as well as outer space, admirably completes the mission.

Perhaps that explains why, despite the necessity of gathering many anecdotes and posthumous personal vignettes from a large community of entertainment personalities and family members, the book still feels more like a nostalgic conversation between friends (now in different realms of existence) than a chronology of legacy-building achievements, of which there were many.

I found myself absorbing contrasting and similar slices of two fascinating lives, nodding in agreement one moment, wincing in exasperation the next, at times even feeling the lead weight of shared griefs and unresolved misunderstandings.

While both of these remarkable friends have indeed lived long and prospered, the struggle has been real. And as LEONARD illustrates so poignantly, the enigma remains. Fascinating…