The journal 4OR: A Quarterly Journal of Operations Research publishes in almost every issue a state-of-the-art survey authored by a well-established scholar on invitation by the editors, who try hard to solicit papers dealing with important or emerging fields of OR. There is a long standing triennial collaboration between the journal and the Annals of Operations Research. The editors of 4OR collect the surveys that appeared in the last three volumes and, invited by the editor of the Annals, serve as guest editors to a volume that collects them. As the first three volumes of this Annals series was very successful, it was decided to continue it. The present volume collects the twelve papers that appeared in the triennium 2012–2014 of 4OR. The authors were given the opportunity to correct, revise, update, and sometimes substantially improve their past work. We therefore wish to thank all of our past survey authors for agreeing to such an endeavor. In the first article of the volume the reader will find an introductory description of these surveys as well as of those that were published in the previous volumes of the series: we believe that the 45 surveys published so far offer an in depth coverage of many hot fields in operations research.