Automatic graphic object layout methods have long been studied in many application areas in which graphic objects should be laid out to satisfy the constraints specific to each application. In those areas, carefully designed layout algorithms should be used to satisfy each application's constraints. However, those algorithms tend to be complicated and not reusable for other applications. Moreover, it is difficult to add each user's preferences to the layout scheme of the algorithm. To overcome these difficulties, the author developed a general-purpose interactive graphic layout system GALAPAGOS based on genetic algorithms. GALAPAGOS is general-purpose because graphic objects are laid out not by specifying how to lay them out, but just by specifying the preferences for the layout. GALAPAGOS can not only lay out complicated graphs automatically, but also allow users to modify the constraints at run time so that users can tell the system their own preferences.