Raising children equipped with 21st century skills is one of the primary goals of today's educational philosophy. In this context, the increase in philosophy programs for children that the main goal is to develop critical thinking skills has led to the need to examine the materials used in the programs. Along with these need, the six books published from 2006 and admitted socially examined in terms 35 critical thinking skills by Paul et. al. (1989) and his colleagues. These are the three the most published books in the philosophy book series and the three with the least number of publications. The case study method, which is one of the qualitative approaches, is used in the study. The data of the study are obtained by descriptive analysis method. It was concluded that the books examined in the Crunchy Philosophy series are resources that can achieve the goal of developing critical thinking skills.