James R Hall's "Am I Still There?" (short story, immortality, free): Medical advances raise the philosophical issue of personal identity
This is the story of Vincent Bonard Lee, 409 years old. He's had practically every part of his body replaced over the years, sometimes multiple times. Now the time has finally come to replace his brain, & the man is wondering how it will affect his idea of himself.
Fact sheet.First published: Analog, September 1963.
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Among the stories from Astounding/Analog issues edited by John Campbell.
Related: Immortality in fiction.