A new rationalist self-improvement book: the 12 Levers

Spencer Greenberg (with Jeremy Stevenson) announces The 12 Levers, a 2026 rationalist self-improvement book that maps ~500 extracted techniques from 100+ self-help books and 20+ therapies into 12 high-level psychological strategies. The authors emphasize that many techniques are recycled (e.g., mindfulness shows up in ACT/DBT/MBCT under different names) and that evidence quality varies: a 2025 cold-exposure meta-analysis produced mixed short- and medium-term findings (benefits at 12 hours and after 30 days but not consistently at other time points or at 90 days), while energetic/Wim Hof breathing has limited rigorous support. They argue people control only four domains—body, communication, thoughts, attention—and provide practical guidance and a Unique Traits Test (80+ traits) to personalize technique selection. Community response on LessWrong was minimal and did not substantively engage the book's claims.