Judith Viorst was born and brought up in New Jersey and now lives in Washington, DC. Her books include the beloved Alexander and the Terrible, Horrible, No Good, Very Bad Day, and its many companion books; adult fiction and nonfiction including the New York Times bestseller, Necessary Losses; poetry for children and adults, and four musicals.

Her most recent book of poetry for children, What Are You Glad About? What Are You Mad About? was published in 2016. Lulu Is Getting a Sister is the fourth book in the Lulu series.

Lane Smith is the creator of It's a Book, It's a Little Book, Grandpa Green and A Perfect Day.

In 2017 he won the CILIP Kate Greenaway Medal for There Is a Tribe of Kids. Lane Smith and his wife, the designer Molly Leach, live in a small town in rural Connecticut, USA.