In every creative writing program, an insanely big deal is made of Voice—discovering a Voice, having a Voice, having a unique Voice, maintaining your unique Voice, I can’t follow the story but oh that Voice, yes it’s misogyny but what a Voice!

The concept of voice is another in the long list of writing program sillynesses (others: science fiction isn’t legitimate writing, it’s not O.K. to admit influence from well-known writers, and the word poignant means something). But there is no doubt that having a singular voice in one’s writing can help talk one’s way from tattered manuscript to cloth-bound, ISBN’ed, publicity-toured book. It’s one of the rare places where writing program, lit mag, and acquisitions editor office overlap: great voice = great writing (= great $).

Writer and This American Life storyteller Sarah Vowell—author previously of The Partly Cloudly Patriot and other books—has such an amusing spoken voice—as any six-year-old or Daily Show watcher can now tell you—that Pixar had her voice the character of Violet in The Incredibles. Coming out of a kid’s mouth, her voice is squashed, the breaks and rasps always audible in her NPR and book-tour readings seemingly all that’s left. Coming out of the real-life, adult, on-the-page Sarah Vowell, though, her voice is the spillings out of anyone awkwardly and energetically overcompensating.

And, boom, there’s her charm, and the charm of Assassination Vacation, Vowell’s latest book-length road trip along another unnoticed plane of American history, in this case the tourism of American presidential assassinations.

Lest you wonder how this could be a worthy subject, Vowell offers that there’s a parallel to relical pilgrimage, which speaks to the supposed fervor or irrationality of those who would abandon all security to travel a thousand miles to inhale the healing dust of a saint. But Vowell’s obsession (and voice) affixes itself instead to the caretakers of American reliquaries—the tour guide of the house where John Wilkes Booth stopped to resupply after shooting President Lincoln; the ranger in charge of Dry Tortugas National Park, where Booth’s doctor/convicted accomplice was imprisoned; the manager of the freakish Oneida Community mansion in upstate New York, where lived the serially unpopular Garfield assassin Charles Guiteau. If medieval pilgrimage speaks more about the pilgrim than the saint, then it undercuts the fun of Assassination Vacation that only conscripted schoolchildren, the elderly, and Sarah Vowell actually visit these places. She has no pilgrims to talk to. Her writing about the caretakers—people largely there by dint of circumstance, people who grew into their interest rather than stalked it—feels like an editorial save more than the heart of a good story.

Aye, but the Voice. Vowell’s style really is the engine of her books, and her “shenanigans,” as she and This American Life boss Ira Glass call her tangents, have coalesced into a discreet skill to pack researched and lived events into the smallest page-space possible. Her seeming desperation to push her imagination in every historical-narrative direction leads to well-earned, well-appreciated, and well-Voiced wonderings like the following:

My head tells me autopsies after murders are routine, that before Ford’s Theater turned into a shrine it was a crime scene, that of course the evidence of the crime was analyzed, then archived, that Abraham Lincoln was not just a martyr or a myth but a case file, what the pros nowadays call a “vic.” So the evidence here calls up the corporeal presence of Lincoln (pieces of his head—gross—and Booth, who bought this very bullet, put said bullet in his pistol, then into Lincoln, which struck the skull, thereby chipping off these little pieces of it, mashing the bullet itself. These well-labeled, well-lit artifacts also suggest the existence of: the autopsy surgeon, the file clerk who catalogued and stowed them, the curator who decided to put them on display, the carpenter who built the display case, etc.

It’s always a fine thing when writers get readers to sneak their minds into freshly hewn nooks. The large-context problem though with Assassination Vacation is that Vowell provides no hierarchy. Despite the aggressive leveling of story structures in the last decades, readers still need a way to know what things are more important than other things. Vowell’s voice doesn’t allow this, because she’s equally excited about everything. It’s an intoxicating enthusiasm, to be sure, but only for a time. She pulls the reader along with her to obscure sites, to view obscure plaques, to reflect on obscure statues and houses and legends, but in the end she violates another writing program rule, one that’s actually true—and she admits as much—that stories don’t work if their only force for cohesion is coincidence. Coincidence, after all, is only in the eye of the beholder.

Thus, there are some buried gems of American history in Assassination Vacation but without an organizing force beyond Vowell’s own Voice, beyond her own obsessions and will, you might find yourself asking to be let off the tour.