India, July 27 -- As a puzzle setter who is very conscious about acknowledging sources for puzzles that are not my own, one question I often ask myself is: having adapted an existing puzzle into a new setting, have I really made it my own? The answer is usually no.

This week's main puzzle is a special case. I have adapted it from a wonderfully engaging puzzle involving the arrangement of 11 items. What makes my version different is that, besides changing the setting, I have added a few extra conditions to the original. That still does not make it exclusively my puzzle, of course. The original appears in A Mensa Book of Logic Puzzles by Alan Wareham (Orient Paperbacks).

#Puzzle 205.1

Eleven classic novels stand in a row on a bookshelf i...