Fr. David Knowles, OSB, FRHistS was born Michael Clive Knowles and was given the name 'David' when he joined the Order of Benedict in 1923. He was a historian and professor at University of Cambridge from 1947 to 1968 and served as president of the Royal Historical Society from 1957 to 1961.
*Note: there is more than one author named 'David Knowles,' however this particular individual is the most widely published.
This book is by a scholar and perhaps other scholars are his main audience. The author delves into the other people around Becket. To be honest I felt like I learned more about Becket and his story in the biography I finished reading recently on Queen Eleanor by Alison Wier but this added some background that the other book did not have.