The files relate to USAF investigations into UFO from 1947-1969. They were conducted under ‘Project Blue Book’ which ended in 1970. More than 700 cases remain unsolved, accounting for 5.5% of the files
There is plenty of work for amateur investigators to try to come up with explanations they never had time to consider or research,’ Nigel Watson author of the UFO investigations Manual told MailOnline …. http://www.dailymail.co.uk