Note: In 1957 Rolf Riekher, an optical engineer by training and profession, published Fernrohre und ihre Meister (a revised edition appeared in 1990). Like Henry C. King’s The history of the telescope, Riekher’s book is one of the classics of the field and remains indispensable for all those interested in the history of the telescope. In May 2007, on the occasion of Riekher’s eighty-fifth birthday, a colloquium was held in his honour at the Archenhold Observatory in Berlin-Treptow, close to his home and place of work. The volume under review, appropriately titled Der Meister und die Fernrohre, is a Festschrift.