This one comes from Provocation and may perhaps serve as an additional explanation of something that seems to be not quite explainable.
Nic tak nie podnieca dziś wydawców i autorów, jak książka, której nikt nie musi czytać, ale każdy powinien mieć.
Stanisław Lem
The EN for the above goes, more or less, like this: "Nowadays, nothing can excite publishers and writers like a book which nobody needs to read but everybody must own". Sorry about poor translation; just trying not to deviate from the source...
I might have already posted this quote somewhere, sometime, but as the words represent a Veritable Solemn Truth, I suppose repeating won`t hurt.
:D