This text is the second version of the "collegediktaat" which accompanies the two-semester course on Mesoscopic Physics offered by the Department of Applied Physics of the Delft University of Technology. The course, coded TN 385 (formerly C29c), is configured to be an introduction into an area of solid state physics which has seen a very rapid development during the last decade, a development which is still continuing and forming new branches. This text contains the material that was felt to be most appropriate for understanding and appreciating the developments in the field. It intends to serve as a survey of the field, allowing advanced undergraduates and starting graduates to obtain a global overview.