Professor Williams field of study is astrochemistry, involving the study of molecular line emissions in outer space to analyse and interpret the evolutionary process of the universe. He led research groups at both Manchester and London and produced more than 300 publications in journals and books. His particular interests are the chemistry of the very early universe, the formation of low and high mass stars and the formation of hydrogen in the universe. He served as
President of the Royal Astronomical Society for 1998–2000. ==Honours and awards==