 This is the last album to feature drummer Aquiles Priester.The title comes from the medieval text of the same name attributed to Thomas Aquinas, which was later used by Carl Jung for relating dreams to the different states of mind.The album is not a concept album as "Temple of Shadows" was, but it rather focuses all lyrics on the different mental disturbances, such as suicide, schizophrenia, sociopathy, bipolar disorder, etc.