“These are very personal tapes,” said Tamsen Harward, a manager at Chorion, the company that controls Christie's literary properties. “There are bits and pieces of the autobiography that could be reviewed, in light of listening to the tapes.”

And in a mystery that might have piqued the interest of one of Christie's fictional sleuths, only the final third of her life story can be heard on the recordings.

“We believe that, being a frugal woman, she reused the tapes,” Ms. Harward said, adding that Christie “clearly” did not feel the recordings had any historical value.

Her modern-day admirers may disagree. The tapes were dictated on a reel-to-reel recorder that was abandoned in the same box with the 27 reels of tape. With an occasional crackle in the background Christie can be heard talking about writing, about her characters and how she conceived them, with her tone varying from casual and meandering to crisp and professional.

“They're extraordinary,” said Laura Thompson, Christie's biographer. “Nobody sounds like that anymore. She's old England. She sounds like an Edwardian, like a gentlewoman. It's as though she's suspended in an early-20th-century world where the social order is intact, and murder is only conducted in a socially acceptable arena - arsenic in the crumpets, or something.”

Agatha Mary Clarissa Miller was born on September 15, 1890, to a wealthy American father and British mother. She married twice and kept a low profile, sometimes refusing to allow publishers to put an author photo on her books.

... contd.