"Genetic Programming Theory and Practice IV" is a comprehensive collection of contributions that emerged from the fourth workshop at the Center for the Study of Complex Systems at the University of Michigan. This academic book provides a platform for the exchange of ideas and information in the rapidly growing field of genetic programming (GP). The contributions come from leading international researchers and practitioners who examine the similarities and differences between theoretical and empirical results related to real-world problems. The text highlights the synergy between theory and practice and offers a comprehensive overview of the current state of GP applications. This publication marks a significant advancement in the field of genetic programming, as GP increasingly shifts from handcrafted software, primarily used in academic research, to an engineering methodology applied in commercial applications. The book is an essential tool for academics, researchers, and professionals engaged in genetic programming, evolutionary computation, machine learning, and artificial intelligence.