Children’s publishers from coast to coast hosted parties as staffers donned costumes based on their favorite characters and books—both classic and contemporary. We’ve gathered a selection of photos from the festivities.

Macmillan’s First Second imprint as Pumpkinheads, the fall-themed graphic novel by Rainbow Rowell, illustrated by Faith Erin Hicks.

Katie Halata, associate director of school and library marketing at Macmillan, dressed as Amelia Earhart, who is featured in Steve Sheinkin’s nonfiction book Born to Fly.

The Macmillan Children’s publicity team representing the move to their new building at 120 Broadway in New York City.

Author Stephen Savage (The Babysitter from Another Planet) as master of the macabre Edgar Allan Poe.

The Holiday House team in full regalia.

Bloomsbury senior production editor Barbara Darko channels Bunnicula.

Kate Sederstrom, editorial assistant at Bloomsbury Children’s Books, as the titular mouse in If You Give a Mouse a Cookie.

Bloomsbury Children’s Books editor Allison Moore assumes the role of detective Shelby Holmes from Elizabeth Eulberg’s The Great Shelby Holmes and the Haunted Hound.

Several Simon & Schuster staffers drew inspiration from the many children’s books coming out this fall honoring teen activist Greta Thunberg.

Jon Anderson (r.), president and publisher of Simon & Schuster Children’s Publishing, and Richard Ackoon are Sophie Johnson: Unicorn Expert.

The publicity department at Candlewick Press dressed as Calico, Fuzzy, Yellow, and Floppy from the Bears on Chairs series by Shirley Parenteau, illustrated by David Walker. (From l.): Anna Abell (Calico), Jamie Tan (Fuzzy), Stephanie Pando (Yellow), and Rachel Johnstone (Floppy).

An array of Candlewick staffers in their costumes, with a special appearance by the Candlewick Bear.

(From l.): Little, Brown staffers Bill Grace, Andrea Colvin, Emilie Polster, Savannah Kennelly, Stefanie Hoffman, Valerie Wong, and Natalie Cavanagh act out author Bob Shea and illustrator Zachariah OHora’s Who Wet My Pants?

Esther Cajahuaringa, assistant editor at Little, Brown Books for Young Readers, as one of Drew Brockington’s CatStronauts.

The winner of the Best Disney Character costume: publicity director Seale Ballenger transformed into Maleficent from Sleeping Beauty.

Disney’s Best Group Costume prize went to the Thunder Trucks group, which took a page from the picture book by Cheryl Klein and Katy Beebe, illustrated by Mike Boldt. (From l.): Heather Crowley as Bulldozer, Cassidy Leyendecker as Tanker Truck, Christine Collins as Fire Truck, and Ian Byrne as Dump Truck.

The First Book team in a tribute to Mo Willems’s characters.

Additional staffers from First Book pay homage to Blair Thornburg’s Skulls!, illustrated by Scott Campbell.

Insight Editions editor Hilary VandenBroek as Neil Gaiman’s raincoat-clad Coraline.

Amanda Ng, senior editor at Insight Editions, conjured a crafty costume based on the forthcoming Harry Potter: Knitting Magic.

Scholastic’s panel of costume judges, (from l.): author R.L. Stine and staffers Mark Seidenfeld, Deimosa Webber-Bey, and Karen VanRossem.

Scholastic marketing colleagues Geoff DeCicco and Mara Lander as Ms. Frizzle and Liz, her pet lizard.

Scholastic’s sales department as Rebecca Elliott’s Unicorn Diaries series.

Popping in from maternity leave, Graphix editor Megan Peace, and her new baby, Gunnison, in Corduroy attire.

(From l.): Nancy Inteli, Alyson Day, Manny Blasco, Megan Ilnitzki, and Luana Horry at HarperCollins reenact The Cool Bean by Jory John, illus. by Pete Oswald.

Publicists at HarperCollins bring to life Laura Ruby’s Thirteen Doorways, Wolves Behind Them All: (back row, from l.) Jenn Corcoran, Lisa Calcasola, Stephanie Macy, Aubrey Churchward, Sari Murray, Sam Benson, Lindsey Karl, Mitchell Thorpe, (front row, from l.) Kadeen Griffiths, Reidden Sewell, Lena Reilly, Jackie Burke, and Cindy Hamilton.

Mckenzie Berry at Random House makes a “practically perfect” Mary Poppins.

Barbara Marcus, president and publisher of Random House’s children’s division, dressed as the Gemini Salem Witchcraft Trial, representing Elizabeth Proctor and Judge Cotton Mather.

Random House’s Regina Flath, cover designer of Wilder Girls by Rory Power, brings her design to life.

During the “Great Penguin Bake Off: Spooky Edition,” Penguin Young Readers employees competed with their confectionary goodies to be crowned Star Baker. This year’s winner was Melissa Faulner from Dutton (r.), with There’s Someone Inside Your Cake. Naomi Duttweiler from the PYR publicity team won the People’s Choice award for her Franken Surprise.

The winning entries in the “Great Penguin Bake Off”: There’s Someone Inside Your Cake and Franken Surprise.

“Rebel Girls” throughout history: (back row, from l.) staffers Kristen Klemens as Amelia Earhart, Karen Chau as Yoko Ono, Michon Vanderpoel as Jeanne Baret, Grace House as Rachel Carson, Pam Gruber as Agatha Christie, and (front) Lauren Zuhl as Peggy Guggenheim.

Lerner Publishing Group’s Halloween party featured beloved office dog Percy.

Magination Press, the children’s imprint of American Psychological Association, dressed up as the coven of witches and wizards in Frank Sileo’s picture book Snitchy Witch, illustrated by Mackenzie Haley.

Capstone got in the Halloween spirit by hosting trick-or-treaters, pumpkin painting, games, a potluck, and a costume contest. Associate editor Abby Huff snagged overall “Best Costume” as Mr. Rogers, creative brand designer Bob Lentz won “Most Creative Costume” for Ray, the Menards Spokesperson, and web content developer Rachel Lense won “Scariest Costume” as the Joker.

Workman’s Gordon Whiteside (l.) as Burt the Chimney Sweep, and James Williamson as a pirate.

The team at Levine Querido in New York celebrates Bye, Penguin! by Seou Lee, one of the publisher’s debut picture books in translation, coming from Korea in fall 2020.