Job, Ecclesiastes and the Book of Proverbs belong to the genre of wisdom literature, sharing a perspective that they themselves call the "way of wisdom".[28] Wisdom means both a way of thinking and a body of knowledge gained through such thinking, as well as the ability to apply it to life. It is attainable in part through human effort and in part as a gift from God, but never in its entirety – except by God.[29] The three books share attitudes and assumptions but differ in their conclusions: Proverbs makes confident statements about the world and its workings that are flatly contradicted by Job and Ecclesiastes.[30] Wisdom literature from Sumeria and Babylonia can be dated to the second millennium BCE.[31] Several texts from ancient Mesopotamia and Egypt offer parallels to Job,[32] and while it is impossible to tell whether the author of Job was influenced by any of them, their existence suggests that he was the recipient of a long tradition of reflection on the existence of inexplicable suffering.[33]