Let us forget for a moment that some of these false tales produced positive effects, while others produced horror and shame. All created something, for better or worse. Nothing in their success is inexplicable. What represents a problem is rather the way they managed to replace other tales that today we consider true. Some years ago, in an essay of mine on fakes and counterfeits, I concluded that although instruments, whether empirical or conjectural, exist to prove that some object is false, every decision in the matter presupposes the existence of an original, authentic and true, to which the fake is compared. The truly genuine problem thus does not consist of proving something false but in proving that the authentic object is authentic.
Serendipities is a collection of essays by Umberto Eco chronicling the attempts of linguists and historians to trace language back to its original form, the mother tongue or linguistic matrix that forms the basis for all modern language and grammar. In tracing it back, he also touches extensively on the topics of religion, natural instinct, conspiracies, and various historical events that either prove or illustrated the points he's trying to make.
In all honesty, this was a pretty nerdy book. I really enjoyed it, but unless you have a vested interest in linguistics, it's probably not going to be too appealing. Eco does write in a very accessible style, even when talking about complex, unfamiliar concepts, so if you want to dip your toes in this might be a good place to start. if you just want to read some Eco though, I'd suggest picking up The Name of the Rose.