The book offers condensed summaries of twenty-three major models of skill acquisition and expertise development presented by leading researchers during the last half a century of classic and new research. This book presents new researchers in learning, training, cognitive sciences, or education disciplines with a big picture starting point for their literature review journey. The book presents an easy-to-understand taxonomy of twenty-three models which can give new researchers a good bird's eye view of existing models and theories, based on which they can decide which direction to dig further. The reviews in this book are complemented with over 200 authentic sources which the readers can refer to for a detailed and deeper dive and set the direction for their further exploration. This book would also act as an essential reference for training & learning professionals and instructional designers to design research-based training curricula to develop the skills of their staff.