The planes of Eora are not well understood among mortals, definitely not among the common-folk. Some scholars, such as Muldefix the Elder, have gone to great lengths to study and even travel much of the inner and outer regions of the Cosmos. The work left behind by these academics has been studied and re-studied over aeons, few daring to tread where they have.
"It is beautiful, out there in the vastness of the Astral. Every day I long to return, to put my body to rest and use my soul to explore the vast cosmos... If I return there, I shan't be back." - Muldefix the Elder, his last words before disappearing, presumably into the outer planes.Though not often travelled, the Inner Planes are better understood than the Outer, which are considered the gods' demesne and not to be trifled with. Adventurers, scholars and wizards sometimes make perilous journeys into the inner regions however, such as the Elemental Planes or Sigil, if their need is dire.