First edition, first printing. i-xii, 13-120pp, illustrated with line drawings and diagrams in text. Pale blue cloth-covered boards with black lettering on spine. 12mo. Cloth has a little uneven fading, gently rounded at corners and a little pushed in a spine ends. Faint tanning on endpapers else neat, clean and tight internally. In its original matte dust jacket, a little shelf worn and faded, gently rubbed on edges.
