This article is from the Puzzles FAQ, by Chris Cole email@example.com and Matthew Daly firstname.lastname@example.org with numerous contributions by others.
What are some long near palindromes, i.e., words that except for one
letter would be palindromes?
Here are the longest near palindromes in Webster's Ninth Collegiate:
catalatic footstool red pepper detonated locofocos red spider dew-clawed nabataean retreater eisegesis possessor stargrass foolproof ratemeter webmember