British author/illustrator team Tom Fletcher and Greg Abbott, who have collaborated on six previous interactive picture books featuring magical creatures (seven, if you count the 2021 World Book Day miniature title, There's a Wolf in Your Book), return in this entertaining addition to the There's a ... in Your Book series. As the narrator introduces a sad-looking unicorn, the reader is led on a journey of discovery as to the causes of this magical equine's mood—worry gremlins, as it happens—and is given a series of instructions, from shaking the book to whispering in the unicorn's ear—that might help lift his mood. In the end, the solution is provided by one of Unicorn's friends, himself the star of one of the other books in the series...

The formula for the books in this series—a simple text offering suggestions for actions that readers and listeners can take to participate in the story, paired with bright, colorful artwork—is followed faithfully in There's a Unicorn in Your Book, and it's a formula that works. As mentioned in my review of the previous entry in the series, There's a Witch in Your Book, despite the continued use of the formula, the book doesn't feel repetitious or reductive, but rather, engaging and fun. Like all of its predecessors, this would make an excellent story hour selection, one that will keep younger children entertained and involved. It would also work at bedtime, with one-on-one reading between parent (or caregiver) and child. The appearance at the end of the book of the stars of the six other books in the series is a nice tie-in and reward, for readers already familiar with their adventures, but it is not necessary to have read those other titles to enjoy the conclusion. ( )