I received in another thread a great description of the oWoD Umbra:
"In the oWoD the whole of the spirit world was called the Umbra. The Umbra included everything, and was subdivided in relation to concepts and "closeness" to material world. So there was the Dark Umbra (the abode of ghosts) the Middle Umbra (where the spirits of Earthly things live) and the High Umbra (where the spirits of more conceptual spirits live). There were also countless Realms that dealt with specific things like the Digital Web (a cyber-virtual reality), the Astral Reaches, Wolfhome, and such. The various parts of the Umbra are dealt with mostly in Wraith, Werewolf, and Mage (as the games that went there most frequently) though Mummy and Orpheus also deal with the Dark Umbra while Kindred of the East deals with the Yin (Dark) and Yang (Middle) Umbra as well."
If anyone can list the "top 5" books that describe as much of the above as possible, including its (dangerous) denizens, from the oWoD, I'd appreciate it. Thank you.