Happy Fields. The name given by the Assyrio-Chaldeans to their Elysian Fields, which were intermingled with their Hades. As Mr. Boscawen tells his readers—“The Kingdom of the underworld was the realm of the god Hea, and the Hades of the Assyrian legends was placed in the underworld, and was ruled over by a goddess, Nin-Kigal, or ‘the Lady of the Great Land’. She is also called Allât.” A translated inscription states:—“After the gifts of these present days, in the feasts of the land of the silver sky, the resplendent courts, the abode of blessedness, and in the light of the Happy Fields, may he dwell in life eternal, holy, in the presence of the gods who inhabit Assyria”. This is worthy of a Christian tumulary inscription. Ishtar, the beautiful goddess, descended into Hades after her beloved Tammuz, and found that this dark place of the shades had seven spheres and seven gates, at each of which she had to leave something belonging to her.
Source: H.P.Blavatsky - The Theosophical Glossary