This book was called the _Mishnah_ (from the verb _shana_, "to repeat" or "to learn"). The Mishnah was not the work of one man or of one age. So long was it in growing, that its birth dates from long before the destruction of the Temple. But the men most closely associated with the compilation of the Mishnah were the Tannaim (from the root _tana_, which has the same meaning as _shana_). There were about one hundred and twenty of these Tannaim between the years 70 and 200 C.E., and they may be conveniently arranged in four generations. From each generation one typical representative will here be selected. THE TANNAIM First Generation, 70 to 100 C.E. JOCHANAN, the son of Zakkai Second Generation, 100 to 130 C.E. AKIBA Third Generation, 130 to 160 C.E. MEIR Fourth Generation, 160 to 200 C.E. JUDAH THE PRINCE The Tannaim were the possessors of what was perhaps the greatest principle that dominated a literature until the close of the eighteenth century. They maintained that _literature_ and _life_ were co-extensive. It was said of Jochanan, the son of Zakkai, that he never walked a single step without thinking of God. Learning the Torah, that is, the Law, the authorized Word of God, and its Prophetical and Rabbinical developments, was man's supreme duty. "If thou hast learned much Torah, ascribe not any merit to thyself, for therefor wast thou created." Man was created to learn; literature was the aim of life. We have already seen what kind of literature. Jochanan once said to his five favorite disciples: "Go forth and consider which is the good way to which a man should cleave." He received various answers, but he most approved of this response: "A good heart is the way." Literature is life if it be a heart-literature--this may be regarded as the final justification of the union effected in the Mishnah between learning and righteousness.