“Moonwalking With Einstein: The Art and Science of Remembering Everything” by Joshua Foer (The Penguin Press, 307 pgs., $26.95)

Why did I open the refrigerator door? Where’d I put my keys? What was the title of the book that whosie told me about?

Well, the name of that book is “Moonwalking With Einstein: The Art and Science of Remembering Everything,” and for anyone with even a passing interest in memory, Joshua Foer’s illuminating investigation into the historical, cultural, physiological and psychological aspects of human memory is essential reading.

At once a witty, engaging first-person account of a freelance writer with average recall skills who goes on a year-long training regimen to compete in the U.S. Memory Championship, and an illuminating overview of how memory has been used from the time of Simonides to now, Foer’s book is remarkable, and also remarkably practical.

At the outset, Foer explains that this is not a self-help manual. But at the same time, his investigation into the intense-o world of competitive mnemonists, of the aforementioned fifth century B.C. poet’s discovery of the “Memory Palace,” of Japanese chicken sexers, of veteran police detectives and amnesiacs, provides a window into how our brains work, and what we can do to hone our ability to remember.

Now, with search engines and smartphones, there really is no need to keep the stanzas of T.S. Eliot’s “The Love Song of J. Alfred Prufrock” or Bogey’s “hill of beans” speech from Casablanca locked in your noggin.

The mental athletes Foer meets in “Moonwalking With Einstein” are, indeed, characters. (Ed Cooke, the long-haired, hard-drinking Brit who becomes Foer’s personal trainer, could be played by “Notting Hill” nutball Rhys Ifans.) And, yes, having the neuron power to memorize 4,140 binary digits in 30 minutes is perhaps a little freakish.

But remembering key events from our childhood, our epic jaunt to India, the restaurant where we proposed to our loved one, the chunk of text from Borges, the lines from Dylan’s “Sad Eyed Lady of the Lowlands” — there’s substance there, not trickery.

“Competing to see who can memorize more pages of poetry might seem beside the point,” Foer says, reflecting on his run in the Memory Championship. “But it’s about taking a stand against forgetfulness, and embracing primal capacities from which too many of us have become estranged.”