For example, in each successive world, the number of countries increases, while the time an individual spends there decreases.
The mystery, is not the manner of death (for they are always perfectly explicable), but the reason their number and why the victims have always met Gavein.
Meanwhile, Dave's colleague, Wilcox, reads Nest of Worlds, a book that will later drive him to insanity and suicide.
During Dave's stay at the Institute, his friend, Zef, also starts reading Nest of Worlds but, unlike Wilcox, is influenced positively by the book.
After an unsuccessful attempt on his life—this time by the army—Dave starts reading Nest of Worlds as a form of escapism.
Dave also reads notes that Zef had placed inside the book on slips of paper.
The protagonist concludes that the mysterious deaths occurred because somebody had been reading the book in which he is the main character.
Marek Oramus, in a review, argues that the hero does not reach the Catalogue but "ends up [...] in hell, degraded by three levels" to one of the embedded worlds.
[1] However, whatever the place in which Gavein finds himself after his suicide, it seems highly unlike any kind of hell as his surroundings in the final scene are all more beautiful than before.