Book excerpt: This book constitutes the refereed proceedings of the 9th International Conference on Persuasive Technology, PERSUASIVE 2014, held in Padua, Italy, in May 2014. The 27 revised full papers and 12 revised short papers presented were carefully reviewed and selected from 58 submissions. In addition to the themes of persuasive technology dealt with in the previous editions of the conference, this edition highlighted a special theme, i.e. persuasive, motivating, empowering videogames.