On a recent evening in Boston, John Flansburgh and John Linnell, better known as the band They Might Be Giants, swept into a staid Borders bookstore in a building that was once home to a bank.
Mr. Flansburgh wore powder blue Adidas sneakers and carried a deep-red electric guitar. A few steps behind him, Mr. Linnell cradled an accordion.
But rather than the usual album tour, this gig was to promote the band's first book, "Bed, Bed, Bed."
The motley clutch of fans crowded around a makeshift stage near the bank's old vault swiveled their heads. Outside, a few bundled devotees peered in through the windows. There were purple-haired, red-haired, and dreadlocked college students wearing thick-rimmed glasses. An older man in a hat and overcoat sat beside an older woman on a leather couch and smiled as Flansburgh cheerily called out, "See you soon, Dad."
There were adults without children. And parents with their kids - but not many kids.
The dearth of small people was surprising considering "Bed, Bed, Bed" is a children's book. But Flansburgh and Linnell admit that most young readers discover their music through their parents.
The handful of children staring up at the stage looked a bit bewildered. One little guy clutched an orange broom, perhaps hoping for "I Am Not your Broom" - track 12 on their 2002 album "No!"
Instead, Linnell produced a stylophone and kicked off the set with "Particle Man." The instrument is played with a pen, he explained, which is "especially appropriate for a bookstore."
"Highly literary," added Flansburgh.
While They Might Be Giants may have joined the crush of celebrities turned kid-lit writers, they've stayed true to their musical roots, with a CD that tucks neatly into the back of the children's book. In many ways, the four stories of "Bed, Bed Bed" read like quirky liner notes with deft illustrations.
And that's the way they like it.
"Picture books are leisurely, not pushy," says Flansburgh, who fondly remembers the stories of Dr. Seuss and Babar the elephant from his childhood. "They're not trying to teach kids. They're really for entertainment and pleasure."
Even their most devoted fans seem to take pleasure in the ease with which the Lincoln, Mass., natives evolved from alternative rockers to children's book authors.
"They were just about a step away from [children's music] anyway," says Katy Simmons, a violin student at the Boston Conservatory. And she means that "in a good way."
After all, it's not much of a stretch from the '80s hit "Particle Man," to "Impossible," the tale of an "octofish" in "Bed, Bed, Bed." Last year, the band released "No!", its CD foray into family entertainment.
Like their book, the songs on "No!" - including "Lazyhead and Sleepybones" and an early rendition of "Bed, Bed, Bed" - are meant to induce sleep. "No!" even carries a disclaimer: "The end of the album's song sequence is specially designed to expedite slumber, so listeners should not operate machinery or plush animals while listening to the last three songs."
But the bookstore performance was for a more alert audience - at least those able to stay awake past 8 p.m. on a weeknight.
George Hertz discovered the Giants through his son, George. Though on this night he was accompanied by his wife and two daughters. The younger George, a college senior, was at school in Pennsylvania. Anticipating his son's envy, Mr. Hertz planned to let him listen in via cellphone.
At the show's end, Flansburgh's parents, Earl and Polly, still sat on the leather couch. He wears the ubiquitous thick-rimmed glasses of a They Might Be Giants fan, and the pair could almost be mistaken for groupies. They regularly travel to watch the band play. "It's an acquired taste," offered Earl with a knowing smile.