Great article - "Invisible Cities" was my introduction to his work and remains a favorite.

If on a Winter’s Night a Traveller gives the reader the impression that there must be a system at play and gives up some of its secrets easily. However, the re remains a persistent feeling, after reading each section, that there are other connections - threads of deliberate meaning - between them all that slip through your fingers as you desperately try to clutch more and more fragments passing by.

It's one of my favorite books precisely because it generates this feeling and led me to Perec's Life: A User's Manual among other fantastic works.

As a fan of Calvino I will say that If on a Winter’s Night a Traveller is somewhat more enjoyable after you've read a bunch of other Calvino, since it has a somewhat cheeky, self-referential feel and the more you sympathize with the author the more you may like it.

Numbers in the Dark is very good as a place to start.