The series Advances in the Physics of Particles and Nuclei (APPN) is devoted to the archiving, in printed high-quality book format, of the comprehensive, long shelf-life reviews published in The European Physical Journal A and C. APPN will be of benefit in particular to those librarians and research groups, who have chosen to have only electronic access to these journals. Occasionally, original material in review format and refereed by the series’ editorial board will also beincluded. This volume contains the following two reviews:Nora Brambilla et al.: Heavy Quarkonium: Progress, Puzzles and Opportunities Daniel Wicke: Properties of the Top Quark