"It's Not Summer Without You" is a captivating children's book by Jenny Han that explores the challenges of growing up and the complexities of friendship and love. The story follows Isabel, who finds herself in an emotional dilemma between two brothers: Conrad, who is sexy and unattainable, and Jeremiah, who is her best friend. As Isabel tries to accept the changes in her life, she is confronted with the question of whether she is ready to leave the past behind and embrace an uncertain future. This book is a heartfelt narrative about the intersection of childhood and adulthood, encouraging young readers to reflect on their own relationships and the challenges of life.