The experimental aspects of the determination of thermochemical data for the attachment of the aluminum monocation Al⁺ to neutral atoms and molecules are reviewed. Literature aluminum cation affinities (enthalpy scale) and basicities (Gibbs energy scale) are tabulated and discussed. Ab initio quantum chemical calculations at the G4 level on 43 adducts provide a consistent picture of the energetics of the adducts and their structures. The Al⁺-ligand bonding is analyzed in terms of natural bond orbital and atom-in molecule analyses. A brief comparison of the Al⁺ basicity scales and other gas-phase cation basicities is presented.