A one-page question-and-answer column by Mary M. Atwater on the causes and prevention of broken warp threads. It lists eleven possible causes in the loom, the warp material, the warping method and the weaving technique, and suggests a flax-seed dressing for weak warps and a gentle double-beat. It also explains how to replace a broken warp thread without tying knots, using a pin in the web, which matters most for tabby and wool or worsted twill fabrics.