Native and modified cyclodextrins act as robust hosts for a variety of guest species in water, and therefore are at the centre of supramolecular chemistry. Covalently linked cyclodextrin dimers provide many advantages over their native counterparts in binding guest species in terms of their stability, selectivity or flexibility. The studies underpinning this book are based on the two beta-cyclodextrin dimers, N,N?-bis((2AS,3AS)-3A-deoxy-beta-cyclodextrin-3A-yl) succinamide and N,N?-bis(6A-deoxy-beta-cyclodextrin-6A-yl) succinamide and the two gamma-cyclodextrin dimers, N,N?-bis((2AS,3AS)-3A-deoxy-gamma-cyclodextrin-3A-yl) succinamide and N,N?-bis(6A-deoxy-gamma-cyclodextrin-6A-yl) succinamide, in which the two beta-cyclodextrin or gamma-cyclodextrin cavities are joined together through either the C3A or C6A carbons, respectively. The fascinating host-guest complexation events of these linked cyclodextrin dimers with various guest species ranging from small organic dyes to biologically important molecules and polymers will be presented. This book will appeal to people studying or working in the field of supramolecular chemistry.