This is a vintage Treasure Island hardcover published by Grosset & Dunlap as part of their Illustrated Junior Library series. The book has green covers with orange printed title and author. The dustjacket is present, it is damaged with small tears around the edges and a spot of missing paper bottom left corner of the front. The book is 7 5/8" x 5 1/4" x 1." I think this is a 1950s era edition, but haven't been able to confirm.
Treasure Island Robert Louis Stevenson Grosset & Dunlap Illustrated Junior Library