Progress in treating those conditions, in turn, has led to a higher incidence of Alzheimer’s. While average life spans have been getting longer in much of the world—though declining in the United States in recent years—the outer limits of longevity haven’t changed much. Current estimates are that Covid-19 deaths will reduce the average by one year.

That is the backdrop to a remarkable story told by Chip Walter, in a new book entitled “Immortality, Inc.”  He begins with a visit to Alcor, the Arizona-based organization that says it preserves corpses at minus 124 degrees Celsius “in an attempt to maintain brain viability after the heart stops.” (Current “patients” include baseball legend Ted Williams.)

While this life-extending strategy, known as “cryonics,” is often ridiculed, the individuals profiled in his book are highly regarded figures whose initiatives can’t be easily dismissed. What links them is that “they are all troublemakers at heart.” They believe that the “conventional approaches” of most medical researchers and practitioners are, at the very least, misguided.

One key figure in the story is Bill Maris, a venture capitalist with a background in neuroscience. In 2012, dismayed by the lack of research into aging, he began meeting with some of his fellow Silicon Valley leaders, like Google co-founder Larry Page, who took an immediate interest. In short order, recounts Mr. Walter, they met with Arthur Levinson, an Apple board member who had spent 14 years as chief executive of the biotech trailblazing firm Genentech. Less than a year later, Mr. Levinson founded Calico, a company devoted to drug development and extending the human life span. Google kicked in $750 million, as did one pharmaceutical company.

Mr. Levinson’s maverick mind-set shines through in a discussion he had a few years ago with several scientists and doctors. According to Mr. Walter, he asked them how much the average life span would increase if all cancer were eliminated. Most assumed about a decade. The answer, said Mr. Levinson, was just 2.8 years.

The prospect of such a modest return helped inspire Mr. Levinson and his Calico colleagues to concentrate even more intensely on unraveling the mysteries of life-span biology. One of their finds, so far, is a rodent native to Africa that shows “little to no signs of aging.”

It’s too early to tell whether the new wave of research is going to deliver on the promise of longer, healthier lives. Mr. Walter doesn’t really address the question of success-probability until the book’s close, where he declares: “the first breakthroughs are already within our reach.” And in 5 to 10 years, he says, those breakthroughs will be followed by “a series of profound advancements.” After that, “further discoveries will arrest, and even reverse, the aging that evolution long ago foisted upon us.”

As for me, I haven’t yet reached the age of 80, and I prefer to live one day at a time. My grandfather’s ninth decade was not very pleasant for him or his principal caregivers (my mother and father). The idea of striving for immortality strikes me as both arrogant and selfish.

Jerry Lincecum is a retired Austin College professor who now teaches classes for older adults who want to write their life stories.  He welcomes your reminiscences on any subject: jlincecum@me.com