A historical guide on wireless technology during the 1900s. Erskine-Murray details how the technology works amongst photographs of inventions as well as providing scientific diagrams. This charming book is a great piece of history looking at futuristic technology from a 20th century perspective.The book had been kept in generally good condition with signs of wear mostly on the corners. There are signs of wear along the hinge, however the pages are clean and present some beautiful illustrations.