Nathaniel Bowditch was born on March 26, 1773, the fourth of seven children of Habakkuk and Mary Ingersoll Bowditch. His father had once been a sea captain but now struggled to support his family as a barrel maker. At twelve, the boy began serving an apprenticeship with a ship chandler. He was fascinated by the equipment and supplies he sold to seamen and the stories they told and was eager to learn more about the world. Nathaniel set out to educate himself.

Recognizing the young man's intelligence and drive, a number of Salem's leading citizens gave him access to their personal libraries and arranged for him to borrow books from the private Philosophical Library Society.

He was in his early 20s when his apprenticeship ended. Like countless Salem lads before him, Bowditch went to sea. In 1795 he set out on the first of five voyages he would make to the East Indies. Before leaving home, he read journals and studied navigation techniques. While at sea, he spent whatever free time he had poring over John Hamilton Moore's book of navigational tables that was used on most ships at the time. He found and corrected 8,000 errors.

Between voyages, Bowditch published two revisions of Moore's book. By 1801 he had made so many improvements to the original that that an entirely new version was published under his own name. Written specifically so that a sailor with limited education could follow it, Bowditch's The New American Practical Navigator was the first complete and accurate handbook of navigation tables. It provided data on wind speeds and patterns, notes on ocean currents, directions on how to calculate tides, reliable mathematical techniques for fixing locations at sea, a glossary, explanations of rigging, guidance on how to keep a ship's journal, and, of course, extensive instructions on navigation. The London Athenaeum called it the best work of its kind ever published in Britain or the United States.

By the time Bowditch took his last trip to the Indies in 1803, he had attained the rank of captain. But his seafaring days were over. The success of the Practical Navigator won him an invitation to teach at Harvard; later Thomas Jefferson sought him out for the University of Virginia, and West Point was interested, too. Bowditch declined all the offers, preferring to work in business. His position as president of the Essex Fire and Marine Insurance Company gave him the financial security and the time he needed to pursue his other interests.

Bowditch was a founding member of the East India Marine Society, formed in 1799 to assist widows and orphans of Salem's captains and for the "improvement of navigation." Society members also established one of the oldest museums in the United States, now called the Peabody Essex Museum, with artifacts from their voyages to distant lands.

Bowditch encouraged sea captains to keep logs that were as detailed as possible, recording not only latitude and longitude but also navigational hazards and places to take on food and water. The Society duplicated the logs and made copies available to other mariners.

After 20 years with Essex Fire and Marine, Bowditch accepted a position with the Massachusetts Hospital Life Insurance Company in Boston. His salary was five times what he had earned in Salem — a major factor given the immense project he had undertaken. He was publishing his own translations of the eminent French astronomer Pierre Laplace's monumental Traité de Méchanique Céleste. The five-volume work addressed Newton's theory of gravitation and its application to astronomy. It also included the research of prominent European scientists.

Bowditch did not simply translate Laplace. For every two pages of the original, he added three pages of annotations.Bowditch devoted the last two decades of his life to his work on Mecanique Celeste, thus giving English-speaking scientists access to the latest research being done in Europe. The volumes became an essential part of the education of those who succeeded Bowditch.

When Nathaniel Bowditch died in 1838, the Boston Athenaeum claimed that "his fame is of the most durable kind, resting on the union of the highest genius with the most practical talents, and the application of both to the good of his fellow man." He is buried at Mount Auburn Cemetery in Cambridge. A life-size bronze statue of him was erected there in 1846.

The Athenaeum's assessment of Bowditch's contributions turned out to be accurate. His work on navigation is still in use more than two centuries later. Tradition has it that no sailor left port without a Bible, a chest of clothes, a mother's blessing, and his copy of Bowditch.