The Siege of Londonderry was a crucial episode of the Williamite wars that followed the Glorious Revolution of 1689. Catholic forces loyal to the deposed King James II besieged the Ulster city with its garrison under the Governor Robert Lundy. The siege was eventually lifted by the actions of the city’s Protestant Apprentice Boys, and by the breaking of a barrier across Londonderry’s harbour mouth by a relieving force. The successful resistance to the siege became a rallying cry for Portestants and remains a feature of Ulster’s divided religious heritage to this day. This book is the diary of the Rev. George Walker, a Protestant cleric who remained in Londonderry throughout and gives a vivid contemporary picture of the dramatic events.