In Sanskrit a human being is a mānava or a manuṣya, words that mean "of Manu": early Indian texts make Manu the first man, the ancestor from whom humankind descends. He has a page here because a Sanskrit law code, composed many centuries after those texts, speaks in his name. That code, the Manusmṛti, was long ranked the most authoritative of the Hindu law books.
The story told most often about him is the flood. Its earliest surviving version stands in the Śatapatha Brāhmaṇa, a Vedic prose text on the sacrifice. As Manu washes one morning, a fish comes into his hands and asks him to rear it, promising to save him from a flood that will carry away every creature. He keeps it in a jar, then in a pit, then takes it down to the sea. When the water rises he ties his ship to the fish's horn and is drawn up to a northern mountain, and he alone survives. He pours butter and curds into the waters as an offering; a year later a woman, Iḍā, rises from them and calls herself his daughter, and through her he begets the human race. In the Mahābhārata the fish reveals itself as the god Brahmā, and in the Purāṇas, the later mythological compendia, as Vishnu.
The law code gives Manu a different origin. In its first chapter he tells the sages that the Self-existent creator divided his own body into male and female, that the female half brought forth Virāj, and that Virāj produced him. Manu then created ten great seers, Bhṛgu among them. Six more Manus follow in his line, the last of them the son of Vivasvat, the sun; the Purāṇas make that seventh Manu the hero of the flood and the ruler of the present age. The creator taught the law to the first Manu, and he in turn taught it to the seers. When they come to ask him for it, he hands the telling to Bhṛgu, and from there on the book reports what "Manu declared".
Historians read that frame as the work of the book's real authors: an anonymous Brahmin writer, or several, in the centuries around the beginning of the common era. Patrick Olivelle, who produced the first fully critical edition in 2005, reads the code's tight design as one author's plan and places it around the second century CE. Others date it earlier or see a text that grew over time. The years on this page mark that window of composition, not a lifetime.
The voice of Manu teaches a single order for the whole of life. Dharma, the duty and law binding each person, is rooted in the Veda; the Veda is revelation and the law books are remembered tradition, and neither is to be called into question. If a twice-born man, a member of the three upper classes initiated into Vedic study, scorns these two by leaning on the science of reasoning, he is to be cast out as a denier of the Veda. Near its end the same book allows reasoning that does not contradict the Veda. Within that order each of the four classes has its work — the brahmin priests, the kṣatriya warriors, the vaiśya traders and the śūdra servants — and there is no fifth. A woman is guarded by her father, her husband and her sons and never stands on her own. The king rules through punishment, which the code calls the true king.
William Jones, a British judge in Calcutta, translated the code in 1794 as Institutes of Hindu Law; or the Ordinances of Menu. B. R. Ambedkar, who later chaired the committee that drafted India's constitution, led the movement against untouchability; on 25 December 1927, at Mahad, it burned a copy of the law code in public.