Quarrying of limestone and converting it to quicklime was a major vernacular industry around the Irish Sea coasts for many centuries, and it is an aspect of these islands’ industrial legacy that has received little attention. David Johnson has spent years researching it in the field and in archive centers and been amazed by its scale and geographical extent. It is a story worth telling. Up to the nineteenth century, quicklime was shipped from Gower and South Pembrokeshire across the Bristol Channel to Devon, and limestone was shipped from both source areas to coastal lime kilns all along the west coast of Wales from North Pembrokshire to the Lleyn peninsular. Limestone was quarried and shipped from Anglesey to, for example, Harlech Castle when it was first built, and to the Mersey, as well as from North Wales to the Dee and Mersey estuaries. There was a major trade in limestone from West Cumbria to what is now Dumfries and Galloway and to and from the Isle of Man; and across the Irish Sea to and from ports all the way from Galway, round the south and east Irish coasts as far north as Ulster. Most recently, and still surviving, is the export of limestone from North Wales to southern England and Scandinavia.