This is an 18 string acoustic guitar, made by Ralph G. Smith. There is an extended neck joint cutaway that allows access to the 18^th fret, which was patented by Smith. The serial number, 4, leads me to guess this guitar was made in the early 70’s. I understand that he only made 10 of these guitars. This is an awesome addition to any collection.

 It is tuned like a 12 string and plays just as easy as the neck is straight. There is a  crack near the bridge but other than that it is in great shape. Guitar player magazine had an article on these in the early 70’s. Please feel free to email me ( rumpapum-aol ) with any questions or info you may have.