what was this person's profession?
He was an American statesman, attorney, diplomat and writer.
John Adams
John Adams (October 30, 1735 – July 4, 1826) was an American statesman, attorney, diplomat, writer, and Founding Father who served as the second president of the United States, from 1797 to 1801. 
who was the declaration of independence written by It was drafted by The Committee of Five, whose members included John Adams and Thomas Jefferson among others who signed it? Representatives of New Hampshire, New York, Connecticut and others when was it published? 4 July, 1776 was there a preamble? Yes, written by John Adams
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John Adams [SEP] Introduction
John Adams (October 30, 1735 – July 4, 1826) was an American statesman, attorney, diplomat, writer, and Founding Father who served as the second president of the United States, from 1797 to 1801. Before his presidency, he was a leader of the American Revolution that achieved independence from Great Britain, and he served as the first vice president of the United States. Adams was a dedicated diarist and regularly corresponded with many important figures in early American history, including his wife and adviser Abigail Adams and Thomas Jefferson. A lawyer and political activist prior to the revolution, Adams was devoted to the right to counsel and presumption of innocence.