The Book Switch Theory

[Jorge_Stolfi]

As we know, 19 comes after 18, and book N18 is well known.

Was #18 known at the time?  It was in Prague, but the Strahov library is a bit harder to access than the Clementinum/NationalLibrary, and in 2009 most of its books were still not in their catalog.

Simply writing a number without knowing whether it exists elsewhere or has been recorded in a list is already Russian roulette.

As I wrote, maybe Wilfrid had obtained Jacobus's book #19 (which was indeed Hansel and Gretel story in Czech).  Or he had some other reason to trust that #19 would never be found.

And maybe one of the reasons why he decided to "enhance" the signature with chemicals was precisely because one of his informers told him that he found a #18 at Strahov, oops...

All the best, --stolfi