What do you get when J.J. Abrams and Doug Dorst decide to write a book together? A head-spinning investigative piece of interactive literary art.

For those familiar with unreliable narrators, loose ends and looser interpretations, “S.” has all the hidden-narrative goodies you already expect from the man behind “Lost.” In fact, there’s plenty of similarities to be drawn between “S.” and J.J. Abrams’ body of work. Questions of identity (“Alias”), shades of existentialism (“Lost”) and the blending of genres (“Super 8,” “Cloverfield,” “Star Trek”) all help lend the book a sense of gravity.

Abrams’ fascination with found-object storytelling is also on display, but in a much more direct sense than was seen in “Cloverfield.” The physical book functions as a fictional artifact, allowing a more intimate form of voyeurism than a found-footage movie.

The slipcover, in a brief breaking of whatever classifies as a “fourth wall” in literature, tells the reader that this is “a love letter to the written word.” Similar to the once-fabled “House of Leaves,” this book hides secrets between pages, waiting to be found by the careful and patient reader. But, where “House of Leaves” began life as a stack of mismatched papers and fragments of story being circulated and eventually found its way to a consolidated print form, “S.” retains all of the lovely mess that makes mystery-solving that much more fun and engaging. Letters and esoterica are tucked between pages, waiting to be found, or fall out unexpectedly.

The real unexpected part of “S”, however, is how surprisingly well the whole things holds together. For a book with at least four interconnected narratives weaving in and out of each other simultaneously, that’s saying something. Chronological order isn’t always a priority as the stories unfold, but sometimes that’s for the best.

The tale beings as a worn library copy of a mysterious text called “Ship of Theseus,” written by the enigmatic “V.M. Straka” and published after Straka’s disappearance and assumed death, finds itself in the possession of you, the reader. Little is known about Straka, even by “F.X. Caldeira,” the person behind the novel’s translation and publishing. Caldeira’s footnotes provide insight into the text and the author in clinical – and occasionally amusing – fashion. “Ship of Theseus” is presumably a heavily-studied text, as the main event begins with two other voices finding their way into the story.

The copy of “Ship of Theseus” that the reader possesses has been heavily studied and extensively annotated by an academic researching Straka’s identity who seeks to uncover the truth behind Caldeira’s footnotes. While borrowing the book from a library, his handwritten notes begin to become a correspondence with a curious graduate student with similar motivations and secrets of her own. Their conversations become a fourth text to follow, adding to the already significant literary density of “S.”

“Ship of Theseus” itself is reminiscent of Kafka writings mixed with a significant amount of genre pastiche and Greek roots. An amnesiac protagonist goes through trials and tribulations that eventually morph into metaphors for the terrors of uncaring industry and militarization. That’s not to say that anything in “S.” is a slog, however. There’s an obviously apparent amount of enthusiasm and playfulness in the telling of the stories being told that pairs nicely with the amount of effort put into ink colors, what originally seem like printing errors, the state of someone’s handwritten notes, the authenticity of the supplemental material tucked in between pages, the list of things that are meant to be discovered and deciphered is long enough to make even the most analytical head spin.

“S.” could exist anywhere outside of print, and is the kind of book that merits careful consideration and analysis. It’s a rotating carousel of crazy ideas and spinning theories, and its unforgiving nature doesn’t lend well to hand-holding. “S.” isn’t here to walk you through a story. It’s a celebration of the publishing process, of prose writing, and of the inherent joys of reading. It holds true to that “love letter to the written word” promise in more ways than one as things come together and subsequently fall apart.

“S.” is impressively smart, endlessly engaging and filled with secrets and stories waiting to be found. Readers can take as much, or as little, as they wish and still come away with something rewarding. For those with insatiable curiosity or obsessive impulses, there isn’t a better time-sink than “S.”