The "Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun" (also known as "Cool Stars") have been running for 30 years since the first one, organized by Andrea Dupree, was held in Cambridge Massachusetts in 1980. Cool Stars is now a well established workshop, which gathers biennially about 400 worldwide experts in Low-Mass Stars, Solar Physics and more recently also Exoplanets, creating an stimulating cross-disciplinary exchange environment in these fields. Cool Star meetings have a long tradition of presenting cutting-edge science, as shown by outstanding results such as the discovery of the first Extrasolar Planet and the first confirmed Brown Dwarf, which were first announced in the Cool Stars 9 meeting celebrated in Florence, Italy in 1995. Cool Stars 17 will be held at the World Trade Center in Barcelona,Spain, starting with an opening Welcome reception on the evening of Sunday, Jun 24, 2012. Science sessions will run from Monday, June 25 through Friday, June 29, 2012, with the traditional plenary sessions in the morning, splinter sessions in the afternoon focused on topics proposed by meeting attendees, and poster displays with the contributions from all conference participants.