There are two ‘schemas’ that illustrate the structure of the book: ‘Gilbert schema for Ulysses’ and ‘Linati schema for Ulysses’—Wikipedia has both, at least as concise tables. The first one was apparently used in defense of the book against the obscenity accusations. However, I'm afraid that they might make the thing too obvious compared to methodical exploration, so personally I avoid looking at them.

But it's widely known that Ulysses has parallels throughout to both Odyssey and the Bible, so I guess that knowledge might work as the first key.

> whether works of art should be considered greater on account of the complexity of their allusions

Not much sense in self-flagellation for not having knowledge that an author is alluding to—unless you feel that this knowledge is a general requirement. For example, English-language authors throughout the ages and to the modernity considered their readers to be familiar with the Bible, and freely used numerous motives and quotations—that I, of more-or-less atheistic upbringing, never could quite get on the fly, except for obvious ones. Finally decided to bite the bullet and get through the Bible just for this, which I've done in my language and will still have to do in English (frustratingly, the texts' authors didn't have much care for readers' aesthetic sense). However, when Marvel makes another movie that relies on the foreknowledge of the universe and comics conventions, I'll give it a miss.

The thing with the allusions, however, is that getting them is an enjoyment of its own, and a good enough reason for reading centuries-old classics before returning to modern stuff. Not everyone's cup of tea, obviously: as one critic wrote, you should only read books for enjoyment, not because you feel you owe something to your teacher. But if ‘Ulysses’ manages to weave its own narrative from what at that time was considered requisite knowledge for an educated man, combined with political themes, while showing off the author's command of the language and style—sure, I'll agree that it's cool. (Just like Sorokin is currently the best author in Russian simply because he can do what he wants with the language.) OTOH when ‘Family Guy’'s plot is a barrage of almost random citations from pop culture—eh, meh, doesn't look smart.

Here's a nice reminder of the context, that just recently appeared on HN (https://newcriterion.com/issues/2021/4/on-getting-poetry):

> With modernism and postmodernism, each of the arts turned against what had long been considered its defining technique. Just as composers rejected tonality and painters rejected representation, poets stopped writing in verse—the regular patterns of rhythm and rhyme that had been the essence of poetry in every culture since ancient times. In each genre, this rejection was initially experienced as a liberation that made new kinds of beauty possible. The first generation of modernists, and their audiences, knew the conventions that were being dispensed with, so they could appreciate the extent and purpose of the transgression.

> But once modernism itself became the canon, artists and audiences gradually lost the ability to extend or even fully appreciate its achievements, because they never mastered the conventions that modernism overthrew. This great deskilling, combined with the rise of mass media and the democratization of culture, resulted in a fracturing of the arts after World War II. In different ways, music, painting, and poetry each split into two: a cerebral, avant-garde version devoted to extending the modernist experiment; and a popular version that appealed to mass audiences without knowledge of the art’s traditions and conventions. The “serious” artists made a Tantalean bargain with the academy, which gave them a secure living and a measure of prestige while cutting them off from what any artist wants most—an actual audience.