Stephen King's the Dark Tower by Robin Furth

A Concordance, Volume II is the definitive guide to the many worlds, argots, characters, and cross-references -- within the Dark Tower series and among the rest of King's work -- that appear in Books V through VII: Wolves of the Calla, Song of Susannah, and The Dark Tower.
Characters and Genealogies
Magical Objects and Forces
Mid-World and Our World Places
Portals and Magical Places
Mid-, End-, and Our World Maps
Timeline for the Dark Tower Series
Mid-World Dialects
Mid-World Rhymes, Songs, and Prayers
Political and Cultural References
References to Stephen King's Own Work

This concordance for King's epic Dark Tower series details character names, place names, and references to each other, and the rest of King's work.