French astronomer Camille Flammarion (1842-1925) called the study of the heavens 'the science which concerns us most'. He believed that learning 'what place we occupy in the infinite' could delight and instruct, and might even promote an end to war and strife. Flammarion dedicated the present work to Fran ois Arago (1786-1853), author of earlier work on popular astronomy. Since Arago's time, the capabilities of telescopes and other instruments had...