In February 2022, XPRIZE solicited proposals for the Milestone Round of the competition. Over 450 proposals were submitted and reviewed by 70 expert reviewers, making this not only the largest XPRIZE to date but also the world’s largest technical review of carbon dioxide removal projects. In addition to awarding $15M in Milestone Awards to the top 15 teams, XPRIZE also announced the “Top 60” ranked teams from the Milestone Review. Most of these teams are included in this book, and represent many of the best and brightest minds in the carbon dioxide removal industry today.