The evolution and current status of the technique of three-coordinate vertex detectors are reviewed. Data acquisition methods and the recording of the topology of complicated events by means of vertex detectors are discussed, along with the features of such detectors as time-projection chambers, pictorial (jet) chambers, vector drift chambers, and vertex detectors based on straw tubes. Tables of the parameters of the best known gas vertex detectors used in fixed-target and colliding-beam experiments are given.