This week Patrick covers the best in Irish and international history publications for April 2019. This month's books include: 'The Trail of the Kaiser' with William A Schabas, 'New Light on George Boole' with Desmond Mac Hale and Yvonne Cohen, 'The Maamstransna Murders' with Margaret Kelleher, 'The Brigidine Sisters in Ireland, America, Australia and New Zealand, 1807-1922' with Ann Power and 'Aghowle: Where the divil ate the tinker' with Margaret Connolly.