The annotated Sandman: an unofficial collection of notes (preserved on the Internet Archives’ Wayback Machine) on the Vertigo Sandman comics (1989–1996). Gaiman’s link says ‘They are terrific. Between them and
[Leslie S. Klinger]’s annotations, all knowledge is there’ (referring to DC’s own Annotated Sandman volumes).
(Via @neilhimself on Twitter)