The Wonder Weeks answers the question, "Why is my baby cranky, clingy, and crying?" with helpful guidance. Maybe they're experiencing a leap in brain development, after which new skills are mastered, discoveries are made, and perceptions evolve. Fussy behavior might signal that great progress is underway! Better yet, these phases occur on similar schedules for most babies--as explained and mapped out in this book--so parents can anticipate the "stormy weeks" that precede the "sunny weeks." Based on decades of research, this fully revised sixth edition covers the first 20 months of a baby's life and includes: The top 10 things to know and remember about a leap Fun games to support brain development Fill-in-the-blank checklists to help better understand personality and behavior traits Science-based explanations about sleep Fresh insight and recent commentary from new parents who've used The Wonder Weeks Anchor moments to keep new parents sane, especially when they are exhausted and discouraged With 2 million+ books sold, and 4 million+ downloads of the corresponding app, The Wonder Weeks has struck a chord. Join the phenomenon that has been embraced by celebrities, social media influencers, and parents worldwide.