Lee has written books such as <That’s okay, we’re all here for the first time!>, <Where did shadow go?>, <Cat, What to do?!>, <The worry restaurant>, <Mama’s little boy grows up>, and <What do you see?>. Her illustrations can also be found in <The book of nice words>, <Please find Jung Yeonwoo’s sword>, <We all get a thumbs-up>, <Dad the crocodile>, <The fish in the blanket ocean>, and <I’m Larva, student number 7 of class 3-2>.