This study aims to measure the validity and effectiveness of the big book media based on Malind folklore "Napak Tilas Leluhur Malind" to improve the appreciative reading skills of grade IV students. This type of research is research and development (R&D) with the ADDIE (Analysis, Design, Development, Implementation, Evaluation) development model. This research was conducted at SD Negeri 2 Merauke with the subject of a trial of Big Book media products, namely grade IV students. The data collection techniques used were questionnaires aimed at material experts, media experts, and student responses as well as written tests used to see the effectiveness of the media. The results showed that the media of the big book based on Malind folklore "Napak Tilas Leluhur Malind" obtained a validation score of 93% for material experts, 82% for media experts, 88% student responses, and an N-gain score for students' appreciative reading skills , which was 0.73. Based on the scores obtained from material experts, media, and student responses as well as the results of the appreciative reading skills test, it can be concluded that the media of the big book based on Malind folklore "Napak Tilas Leluhur Malind" "Very Feasible" is used and is able to improve the appreciative reading skills of grade IV students in the category "High”.