1966. Sixth Edition. 45 pages. No dust jacket. This is an ex-Library book. Dust jacket laminated to boards. Library copy, with expected inserts and inscriptions. Pages are mildly tanned. Mild cracking to front hinge, missing front free endpaper. Mild thumb-marking present. Boards have mild edgewear with corner crushing and notable marking to boards. Heavy tanning to board edges and spine, which has mild crushing to ends. Book has forward lean.