Complex sentence: Specifying the depth of research, Callan was described by Bryan Forbes as "a shining example" of good biographers in his review and the book was chosen by the Sunday Times as one of its recommended Best Books of 2011.
Split into simpler sentences: Specifying the depth of research, Callan was described by Bryan Forbes as "a shining example" of good biographers in his review of the book. The book was chosen by the Sunday Times as one of its recommended Best Books of 2011.