John Macquarrie FBA TD was a Scottish-born theologian and philosopher. Timothy Bradshaw has described Macquarrie as "unquestionably Anglicanism's most distinguished systematic theologian in the second half of the twentieth century."
Very informative book on the Anglican Sacraments. The chapter on Marriage is quite outdated though but a lot has changed in that regard since the 90s when it was published. Overall though a very very good read.