Colin Dickey at The Believer:
Mercer has long since been placed in the upper ranks of the great palindromists. Over the years he submitted hundreds of palindromes to the British periodical Notes and Queries, including “Now, Ned, I am a maiden won,” “Nurse, I spy gypsies—run!,” and “Did Hannah say as Hannah did?” But outside the world of word game enthusiasts (a.k.a. logologists), he is largely unknown. This despite being the author of a seven-word, mostly inaccurate synopsis of a complex engineering feat that became one of the most widely known palindromes in English.
“A man, a plan, a canal, Panama” works well as a palindrome because it’s not only the same letters read backward and forward, but it also makes sense, which is more than many palindromes do. “Satan, oscillate my metallic sonatas” is a terrific palindrome, but what does it mean?
more here.