Ian Lewis, 43, of Standish, Lancashire, England, was interested in finding out about his family. He spent thirty years tracing his family tree back to the seventeenth century. Thirty years. He traveled all over Britain talking to 2,000 relatives about the family tree. He even planned to write a book about how his great-grandfather left to seek his fortune in Russia and how his grandfather was expelled after the Revolution.  Then, after doing all that research, Ian Lewis made a discovery that stopped him in his tracks. He discovered he had been adopted. By birth, he was not a Lewis at all. He was adopted when he was a month old and his real name was David Thornton.  And so Ian Lewis, alias David Thornton, went back to square one.  He started his family research all over again in light of hi…