This volumes compiles 35 outstanding papers of the leading experts in the field aiming at inspiring, provoking, and educating present and future generations of computational chemists and at preparing them for the challenges of the 21st century. This special edition of selected papers from the famous "Journal of Molecular Modeling" - the first electronic online journal in the history of science - is devoted to the event of Paul von Rague Schleyer's 70th birthday. The papers range from the nonclassical carbocation debate through "STO-3G-lithium" on to his recent work on magnetic properties and NICS. The volume will be used as an extremely useful source for computational, theoretical and physical chemists in industrial research and academia. The readers receive free online access to the electronic supplementary material of the respective papers."