WASHINGTON – Generations of young people have thrilled to the crackling wit of Holden Caulfield, the teenage narrator of The Catcher in the Rye. But if you want to hear an authorized audiobook of J.D. Salinger's seminal 1951 novel, you'll need what amounts to a doctor's prescription.

Salinger died in 2010, without relinquishing the rights for an audio recording. But U.S. copyright law grants the Library of Congress permission to produce an audio recording or Braille edition of any published work for the blind and physically handicapped, provided the book is distributed free, unabridged and, in the case of recordings, on special digital playback equipment.

The library has recorded Catcher twice, both times by the same steady narrator, who has been reading books out loud for most of the past 40 years. Ray Hagen last laid down the Catcher tracks in 1999, at the age of 63, after the original masters had deteriorated. Both times, he says, the approach was the same: "Just read it honestly."

By his estimate, Hagen has recorded over 500 audiobooks in 39 years. If you or someone you know is blind or physically handicapped and borrows those boxy little recordings of books, newspapers and magazines, you've heard Hagen's voice.

Last year, more than 850,000 people got the free materials in the mail through the library's National Library Service (NLS) for the Blind and Physically Handicapped, which just marked its 80th anniversary. Users need permission from a physician or ophthalmologist to access the materials, which usually come through a network of libraries.

The library doesn't keep listener data, but Jane Caulton, an NLS spokeswoman, says their demographic skews older than the U.S. population, with most patrons 65 or older.

Even as commercial audiobooks surge in popularity, the program's recordings remain bare-bones affairs, with no music, no special effects and no multiple voice actors for different parts. Caulton says the library is looking to commercial producers for rights to future titles but adds, "I just can't say what deals have been worked out."

For decades, NLS used records and tapes, setting its recordings apart by making its playback machines operate at unusual speeds: 8⅓ rpm rather than 33⅓, for instance. Now that the recordings are digital, they're stored on special USB thumb drives in a rare .3gp format that most computers can't read. The Braille-equipped plastic thumb drive holders fit only approved machines.

But in this file-sharing era, everything eventually finds its way into the public domain. Sure enough, Hagen's Catcher recordings have made their way onto file-sharing sites and have developed something of a cult following among open-source pirates who happen to be Salinger fans.

Semi-retired since 2001, Hagen has read books out loud since 1973 for NLS, working from a basement studio at the end of a long labyrinth of stairways and gunmetal steel bookshelves in northwest Washington. The studio turns out about 100 audiobooks a year, part of a larger system of library studios across the USA that produces about 2,000 recordings in all.

On a recent winter afternoon, Hagen and a producer sat facing one another through the glass of a soundproof booth as he put the finishing touches on a recording of It Gets Better, a 2011 anthology of writing for gay teens. Since beginning the recording last fall, Hagen had checked the pronunciation of each of the book's 100 or so contributors. He realized he'd gotten a few wrong and was painstakingly rerecording the authors' names.

"We're fiends — fiends — on pronunciation," he says. "Correct pronunciation for an audiobook is the same as correct spelling for a print book."

Hagen's preoccupation even resulted in a hobby that became something of an obsession. He began keeping track of names with a little box of 3x5-inch cards. One box grew to seven, eight, then nine. In 1990, the library finally began digitizing the collection.

The list — dubbed Say How?— now resides on the library's website and one of its most visited pages. Hagen still updates it from time to time — watching TV, he'll notice an unusual pronunciation and jot it down. MSNBC personality Rachel Maddow, for instance, pronounces her own name "MA-do," but everyone else seems to pronounce it "MA-dow."

Asked how a 63-year-old could channel the emotions of Catcher's 16-year-old protagonist, Hagen brushes off the question. "He was a disenfranchised teenager — so was I. And I remembered those years really, really well."

Hagen can't remember if he recorded Salinger's classic Nine Stories collection, but he remembers recording Franny and Zooey. Oh, and it's "ZOO-ee," he says, not ZO-ee.