This is the first comprehensive textbook on Keratorefractive Lenticule Extraction (KLEx). In fact, this new textbook is an expansion and update of the successful book, SMILE, that was published in 2015. The new edition has now been expanded to include all available KLEx procedures such as SMILE/SMILE Pro, SmartSight, CLEAR, and SILK. For the second time, the editors managed to gather a group of excellent international researchers and clinicians from all parts of the world as authors of the individual chapters. The publication follows the proven concept of the first edition, providing a clear, step-by-step approach encompassing the fundamentals, healing response, energy management, biomechanics, complications management, and surgical pattern for KLEx in general and each specific procedure in particular. For the first time, the reader will not only be able to understand KLEx in detail but also to appreciate differences in technologies available on the market.