The Aura is the energy envelope that surrounds and interpenetrates the physical body. The aura is made up of all the different energy shells or layers that are subtle in nature.

Different traditions and authors use slightly different systems or layers. All agree on seven layers, but some include the physical body in there as a first layer, while others see seven subtle layers or subtle bodies around the physical body.

Richard Gerber, e.g., sees the aura as layers that compose the physical, etheric, astral, mental, causal, and higher spiritual aspects of the multidimensional human form. So, he includes the physical body. (See also: biofield)

Barbara Ann Brennan on the other hand distinguishes the following layers

Note that there is a large overlap, where what Gerber calls the higher spiritual bodies coincide with Brennan's Celestial and Ketheric Template layers, the causal body coincides with the Etheric Template Level. The main difference is with regard to the astral body. Many authors, like Gerber, equate the emotional body with the astral body, whereas Brennan sees the emotional body and the astral body as two separate layers.