Double stars are the rule, rather than the exception: our solar system, having a single sun, is in the minority. Orbiting satellites, ground-based observatories and interferometers have all helped discover many hundreds of new pairs - but this has left enormous numbers of wide, faint pairs under-observed or not observed at all. This is where amateur astronomers can help. Bob Argyle, a professional astronomer at Cambridge University, shows where enthusiastic amateur observers can best direct their efforts. The book caters for the use of every level of equipment, from simple commercial telescopes to micrometers and CCD cameras. Amateur astronomers who have gone beyond "sight-seeing” and want to make a genuine scientific contribution will find this a fascinating and rewarding field - and this book provides all the background and practical information that’s needed.