Waddell's voluminious writings after his retirement were based on an attempt to prove the Sumerians (who he identified as Aryans) as the progenitors of other ancient civilizations, such as the Indus Valley civilization and ancient Egyptians to "the classic Greeks and Romans and Ancient Britons, to whom they [the Sumerians] passed on from hand to hand down the ages the torch of civilization".
Waddell's extensive post-retirement works aimed to prove that the Sumerians (whom he identified as Aryans) were the ancestors of other ancient civilizations such as the Indus Valley civilization and ancient Egyptians, including "the classic Greeks and Romans and Ancient Britons," passing on the torch of civilization.