Peer review in Peerage of Science consists of four stages. Each stage has a deadline, set by the Authors upon sending their manuscript and displayed to Peers deciding whether to engage as a Reviewer. In Stage 1: Authors submit a manuscript to Peerage of Science, where it will be available for other Peers to engage as Reviewers. Peers voluntarily engage in review processes to gain the benefits Peerage of Science provides for them. The review has to include a Peerage Essay, a max 1000-word text written in a standardized format, carefully enough to withstand peer review itself. In Sage 2: From now on, the process can be accessed only by Authors, Reviewers, and Editors. Reviewers are notified that they can now evaluate the reviews sent by others. The evaluation is based on the Peerage Essay. By the deadline of Stage 3, Authors either send a revised version of the manuscript, or decide to withdraw the manuscript for later re-submission. Final evaluation is seven scores on different aspects of the revised manuscript (breadth, impact, originality, data, methods, inference, literature coverage), and a free-text comment directed to Editors (but displayed to Authors and other Reviewers as well), where the scoring should be justified and any remaining issues stated. As soon as each Reviewer has completed the evaluation, or at the latest when the stage closes, the peer review process is completed. A quality index (Peerage Article Quality, PAQ) is calculated for the manuscript, according to the final evaluation of the revised manuscript.