Bolsters, Blocks, Barriers by Alastair and Ann Cormack. 1992 1st edition. Large format paperback. This book tells the story of the building of the Churchill Barriers/Causeways in Orkney. Built after the sinking of the Roal Oak by U-47. Published by The Orkney View. Staple-bound and contains 88 pages. Very good, clean condition. A rare book about this incredible project to seal up Scapa Flow and connect the islands of Orkney. See photos for more information. Any questions please ask.