Sewing threads are engineered yarns designed to pass through sewing machines without breaking. They are produced from fibers like cotton, polyester, nylon, silk, and linen. Thread construction involves twisting fibers or filaments together, with the amount of twist and direction of twist affecting the thread's strength and performance. Different thread types are suitable for various fabrics and purposes, such as cotton for breathability and polyester for durability. Thread finishes further enhance qualities like strength and abrasion resistance. Good sewing threads sew easily, make durable seams, and in the case of decorative threads, are aesthetically pleasing.