This is funny. I called my favorite bookstore in Jakarta, asking if it had Tim Harford's Undercover Economist. The person there responded to me: "Sir, is this a follow up of that book -- Confessions of [an Economic] Hitman?". I said no. Then she insisted: "But, is this also a story about espionage? You know, like the Confession?". Sounded like she associated "undercover" with "espionage".
It seems, that the confession book -- now a new bible for many populists and conspiracy theory lovers -- is indeed very popular.