The Home Book of Musical Knowledge by David Ewen

This particular copy of The Home Book of Musical Knowledge by David Ewen was bouhgt by my dad for his mom on November 29^th, 1973. It is in great (almost new) condition. The pages are all intact and are all straight, the words aren't faded, the gold embossing on the hardcover isn't faded, the hardcover isn't damaged in any way. The only problems are that the pages are a slight yellow shade (from age I hope), and that there is a thin line of stain on the sides of the pages that is maybe an inch long. I would also like to mention that this is probably a reprint, since the book (in general) was published in 1954. How much could this book be worth? A fast answer would be quite helpful.