Het Esperanto in Twintig Lessen:

Rotterdam: Zwagers, [1930]. Presumed first printing (not a reprint). Brown octavo, taped binding, 115 p; 21 cm. Clipped edge to spine foot and head, very gently rubbed corners, faint discoloration to top edge to covers, light soiling to covers, mostly to rear cover, spine is taped, faint crease and tiny tear to front edge, front cover-top edge and top-rear cover very slightly edge-torn and rubbed, three pieces tape to joint, ink ownership signature to title page, three spots to front pastedown and title page, else Very Good(-). Paperback.

In Dutch. Esperanto, Languages.