A stapler is a small office tool that joins pieces of paper together by driving a thin metal fastener, called a staple, through them. When you press down on the top of the stapler, a mechanism inside pushes a staple through your papers and bends its ends on the other side, holding everything securely together.

Staplers come in different sizes. The kind you see on desks or in classrooms can fasten about 20 sheets at once, while heavy-duty staplers used in print shops or offices can handle much thicker stacks. Some staplers are designed to reach deep into the center of booklets or magazines.

The stapler was invented in the late 1800s, though early versions were clunky and expensive. By the 1900s, improved designs made staplers affordable and common. Before staplers, people fastened papers with straight pins, which could prick you, or with ribbons threaded through holes punched in the pages.

Today, staplers are so ordinary we barely notice them, but they're remarkably useful devices. They hold together everything from homework assignments to important business documents, and unlike paper clips, stapled papers stay firmly attached even when shuffled around in a backpack or briefcase.