One Swedish summer, a father and son rig up a strange contraption so they can electrocute their lawn. Their intention, of course, is to harvest a large quantity of earthworms, for these are amateur eel fishermen, and amateur eel fishermen are occasionally in want of a giant bucket of worms. The father tells his son to stand back, then hits the juice: “The worms started appearing out of the ground, hundreds of them. … The whole lawn looked like one big living organism.”

So it goes in “The Book of Eels,” Patrik Svensson’s captivating debut (in clearheaded translation from the Swedish by Agnes Broomé), which is told in two distinct and alternating styles: one chapter of accessible nature writing, one of personal vignette. The book is its own strange contraption, all of it similarly shot through with electric current.

The book’s deadpan title perhaps undercuts its depth and complexity. Yes, this is a book about eels, those uncanny creatures, but in Svensson’s capable hands it is also a book about obsession and mystery, about faith and science, and about the limits of knowledge. For as much as we know about the eel in our advanced scientific age, there is plenty that remains hidden. No one knows, for instance, how long eels can live, and some have shown the ability to essentially pause their aging process. No one has ever been able to successfully breed a European eel in captivity, either. The creature is “secretive in a way that comes across as deliberate and preordained,” Svensson tells us.

And while the scientific community agrees that European eels exclusively reproduce in and are hatched from the Sargasso Sea, no human has ever seen these eels mate, nor even spotted a mature eel in the Sargasso Sea, a conundrum that strikes the reader as similar to the way physicists know subatomic particles exist without ever having observed them.

Perhaps most fascinating is the eels’ life cycle: Born in saltwater, they move through four distinct metamorphoses and live the bulk of their lives in freshwater, before finally growing reproductive organs, dissolving their stomachs, and migrating back through stream and brook — occasionally slithering hours across land — until they can once again reach the Sargasso Sea, where they procreate and die.

Like Annie Dillard and Rachel Carson, Svensson knows the best nature writing is done with emotion and drive. “The Book of Eels” is not objective in the way one might expect a work of nonfiction about the natural world to be. Svensson writes with imaginative verve and point of view. He is opinionated, funny, curious and open to disagreement: “A person seeking the origin of something is also seeking his own origin,” Svensson writes about a particular eel scientist. “Is that a reasonable statement?”

This is science writing as done by that convivial stranger at the end of the bar, so thrilled with eel-dom that you begin to edge your stool closer, the better to overhear briny tales of Sigmund Freud’s early eel research, or how tiny ancient Egyptian eel sarcophagi have been discovered.

But what sets “The Book of Eels” apart is its dual nature: Each eel chapter is followed by a brief self-contained chapter of memoir where Svensson reflects on his relationship with his father, a Swedish road paver. Svensson situates us along the banks of his childhood at a spot where “the stream rushed in a startled fashion” and bats swooped “like black punctuation marks against the sky.”

Here, father teaches son the arcane art of eel fishing. These gorgeous vignettes — which detail golden days and bracing swims through unfathomable currents — have something of Tove Jansson’s “The Summer Book” to them. They are elusive and mythic in what they teach about our closest relationships, how our families shape and guide us while remaining somehow unknowable.

Svensson is confident and controlled as he toggles between science and memoir, fact and memory. And only in this delightfully unusual book might you hope to encounter lines like these: “The salmon, which sparkles and shimmers and makes wild dashes … comes off as a self-absorbed, vain fish. The eel seems more content. It doesn’t make a big deal of its existence.” Svensson, however, does make a big deal of the eel’s existence, and we are grateful for it. 

Will McGrath is a writer and journalist in Minneapolis. His debut book, “Everything Lost Is Found Again,” won the 2019 Bernard J. Brommel Award for Biography & Memoir.

The Book of Eels
By: Patrik Svensson, translated from the Swedish by Agnes Broomé.
Publisher: Ecco, 256 pages, $28.99.