A saddle stitch bound book is a type of bookbinding method where folded sheets of paper, known as signatures, are stacked together and stapled along the fold line, creating a booklet. This method involves inserting staples through the centerfold of the folded sheets and clinching them closed. Saddle stitch binding is commonly used for smaller booklets, brochures, pamphlets, and magazines with a lower page count. It's a cost-effective and efficient way to produce lightweight publications with a clean and professional appearance.