The Rev. Dr. Robert (Bob) Letham is an eminent theologian and historian, and a superlative example of Greystone's commitment to careful patristic scholarship and confessional Reformed catholicity. Dr. Letham's 2010 Westminster Theological Journal article on the Westminster Assembly as a Reformed catholic body has been required reading in Greystone's core class on Reformed Catholicity since Greystone's founding. Dr. Letham teaches systematic theology and oversees research degrees at Union School of Theology (formerly Wales Evangelical School of Theology). He previously served as Senior Minister of Emmanuel Orthodox Presbyterian Church in Wilmington, Delaware, and has also taught at London School of Theology, Westminster Theological Seminary (Philadelphia) and Reformed Theological Seminary (Washington DC/Baltimore). Dr. Letham has authored numerous books, including The Work of Christ (IVP Academic, 1993); The Holy Trinity (Presbyterian & Reformed, 2004); The Westminster Assembly: Reading Its Theology in Historical Context (Presbyterian & Reformed, 2009); Union with Christ (Presbyterian & Reformed, 2011); and Systematic Theology (Crossway, 2019). Robert and his wife Joan have three children and three grandchildren, and his interests include cricket, music and walking.