Complex sentence: Andrew Tobias (born April 20,1947) is an American journalist, author and columnist, whose main body of work is on investment, but who has also written on politics, insurance and other topics.
Split into simpler sentences: Andrew Tobias (born 20 April 1947) is an American journalist, author, and columnist. His main body of work is on investment, but he has also written on politics, insurance, and other topics.