The volume forms a part of the celebrations marking the anniversary of the invention of the telescope. From its Renaissance beginnings to yesterday's Cold War, the essays contributed here throw a spotlight on a number of significant episodes in the continuing adventures of this well-loved instrument, which has played a crucial role in Man's thinking about his position - literally and philosophically - in the universe. Drawn from various conferences held by the Scientific Instrument Commission of the International Union of the History and Philosophy of Science between 2007 and 2009, these papers make a substantial contribution to our current knowledge about this fascinating optical instrument.