This file is the presentation made the 15th May 2019 at MPI-EVA: Current publication system and preprints: Main features of the current system of scientific publications - which is particularly expensive and not very transparent -, why we publish and what are the main problems of this system. Possible solution to these problems, the preprints and try to answer these questions: what is it? what are the benefits of using prepints? Peer Community in: a free public system for peer-reviewing and highlighting preprints: In order to offer an alternative to the current system of publication we have initiated the Peer Community in (PCI, https://peercommunityin.org) project. PCI is a non-profit scientific organization that aims to create specific communities of researchers reviewing and recommending, for free, unpublished preprints in their field (i.e. unpublished articles deposited on open online archives like arXiv.organd bioRxiv.org). Each PCI is a group of several hundred recommenders playing the role of editors who recommend such preprints based on peer-reviews to make them complete, reliable and citable articles, without the need for publication in ‘traditional’ journals (although the authors can submit their recommended preprints afterwards). Evaluations and recommendations by a PCI are free of charge. When a recommender decides to recommend a preprint, he/she writes recommendation text that is published along with all the editorial correspondence (reviews, recommender's decisions, authors’ replies) by PCI Evol Biol. The preprint itself is not published by PCI: it remains in the preprint server where it was posted by the authors. The first Peer Community In was launched in 2017: Peer Community in Evolutionary Biology (PCI Evol Biol). More than 380 recommenders have already joined PCI Evol Biol. PCI Paleontology and PCI Ecology were launched in January 2018 and the latter already has 280 recommenders.