'Dedication' and 'The geometry of chemical reactions in single crystals' in Physics of the solid state: commemoration volume to Professor S. Bhagavantam (Academic Press, 1969) Background material: 'Temperature dependence of the single-crystal reaction: anthracene photooxide to (anthraquinone/anthrone) + H O, etc.', 7pp typescript by Lonsdale and E.Nave (1966); 'Real crystals as a source of error', 18pp typescript and captions by H.J. Milledge (1968). 1966-1968