The children's book series that is about a rat is called "The Tale of Despereaux" by Kate DiCamillo. This enchanting story follows the adventures of Despereaux, a brave and curious mouse who lives in a castle in the kingdom of Dor. Unlike his fellow mice, who fear the humans who live in the castle, Despereaux is fascinated by the world beyond his little mousehole. He longs to explore the castle, to gaze upon the faces of the humans who dwell there, to hear their music and stories.
Despite his diminutive size, Despereaux is determined to be more than just a mere mouse. He is intelligent, brave, and compassionate, and he possesses a heart full of love for all creatures great and small. When he meets the kingdom's princess, Pea, he falls hopelessly in love with her, and he embarks on a perilous quest to save her from the clutches of the evil rat, Roscuro.
Throughout the series, Despereaux faces many challenges and obstacles as he journeys through the kingdom of Dor. But he never loses hope, and he never stops believing in the power of love and courage. Along the way, he discovers the true meaning of friendship and loyalty, and he learns that even the smallest of creatures can make a big difference in the world.
"The Tale of Despereaux" is a heartwarming and delightful series that is perfect for readers of all ages. With its lovable characters, engaging plotline, and beautiful prose, it is no wonder that this enchanting story has captured the hearts of readers around the world. So if you're looking for a captivating children's book series that will inspire and delight, look no further than "The Tale of Despereaux" by Kate DiCamillo.