There are many books on Piaget's theory, but many of them are difficult to understand and cover a wide range of topics, making it difficult to grasp the big picture.
This book is easy to understand because it clearly shows how the main basic concepts of Piaget's theory of cognitive development are connected from infancy to adolescence.
Furthermore, for Piaget, the empirical and the theoretical are not separate, and this book balances the two by detailing Piaget's direct observations and experimental examples.