Instantly, almost before the sound of the knock died away, Gates opened the door and stepped forward.  The man who stood in the corridor, facing the doorway, was tall, slender, dark of complexion, like a Spaniard or a Mexican.  His black hair was long, straight, thin; his black eyes were bright, treacherous, too close together, with a little vertical wrinkle between the brows.  He was dressed in a neat brown business suit of expensive material.