Book excerpt: This book introduces the local history practitioner to the world of maps - the special character (and appeal) of maps as an historical source, why they are invaluable in local history research, and questions that must be asked of them. The historical background to map creation in Ireland is outlined, with details on the major classes of cartographic and associated material and the repositories wherein they may be found. The Plantation series, travel and county maps, maps as part of published reports and journals, military mapping, estate and property mapping, and maritime maps, historic Ordnance Survey and Valuation Office maps, and more recent OS mapping, including the 1:50,000 Discovery series, are discussed. A section on essential map reading skills, including matters of scale, representation and accuracy, will help equip the researcher to explore this coded world. Step-by-step guidance for starting out to locate maps relevant to one's study area is provided. Case studies of working with maps in local history are offered as practical examples of what can be done, and guidelines for map-making are also included.