Research papers relating to the life and work of Harry Grindell Matthews (1880-1941), whose inventions included an alleged “Death Ray”, radio-controlled boats, aerial mines, laser sky-writing and talking pictures. The material was collected by Jonathan Foster in the preparation of his book “The Death Ray – the secret life of Harry Grindell Matthews” (Inventive Publishing, Gloucester 2008, ISBN 978-0-9561348-0-6) and includes transcripts and copies of documents at The National Archives, as well as oral history interviews (on micro cassette) with people who remembered Matthews. Matthews lived on Mynydd y Gwair to the north of Swansea towards the end of his life.