Children’s book publishers from coast to coast held parties as staffers donned costumes inspired by their favorite characters and books. We’ve gathered a selection of photos from the festivities.

The Candlewick crew as Harry Potter characters (from l.): Amanda Bellamy as Dolores Umbridge; Christine Engels as Professor Sprout; Matt Roeser as Professor Snape (dressed as Neville’s grandmother); Katherine Codega as Bellatrix Lestrange; Nancy Bruckman as the Boy Who Lived; Melanie Cordova as Luna Lovegood; Erin Farley as Tom Riddle’s diary; Lisa Rudden as Professor Trelawney; and Jackie Shepherd as Alastor “Mad-Eye” Moody.

Candlewick’s marketing department dressed as members of the Baby-Sitters Club: (from l.) Jamie Tan as Kristy, Stephanie Pando as Mary Anne, Anna Gjesteby Abell as Claudia, and Rachel Johnstone (seated) as Stacey.

Jason Lin of Candlewick as Julián from Julián Is a Mermaid by Jessica Love.

Kate Sederstrom (l.) and Claire Stetzer from Bloomsbury’s editorial department made a perfect pair as Princess Buttercup and Westley from The Princess Bride by William Goldman.

Bloomsbury staffers dressed up as their favorite children’s book characters.

The HarperCollins Children’s finance team took a page from Amelia Bedelia—figuratively speaking, that is: (from l.): Kristin Chew, Linda Wong, Diana Huang, Alida Egipciaco, and Randy Rosema.

Members of the HarperCollins marketing team won the department’s prize for group costume, drawing inspiration from YA fandom and Kendare Blake’s Three Dark Crowns series. (From l.): Shaelyn McDaniel, Jace Molan, Priya Khanolkar, Mariner Brito, Tyler Breitfeller, Jane Lee, and Ebony LaDelle (in background).

Erin Fitzsimmons (l.) and Barbara Fitzsimmons at HarperCollins emulated Bloom, a picture book biography of fashion designer Elsa Schiaparelli, written by Kyo Maclear and illustrated by Julie Morstad.

(From l.): Holiday House sales coordinator Jessica Dartnell as Arthur, publicity manager Faye Bi as Matilda, and data manager Hannah Finne as Little Red Riding Hood.

Two Tomie dePaola tributes at Holiday House: Grace Maccarone (l.), executive editor, as Strega Nona; and Terry Borzumato-Greenberg, v-p of marketing and publicity, as Santa from The Night Before Christmas.

The Macmillan Children’s publicity squad dressed as campers from Vera Brosgol’s graphic memoir Be Prepared: (top row, from l.): Kelsey Marrujo, Shivani Annirood, Madison Furr, Morgan Rath, and Morgan Dubin; (bottom row, from l.) Alexandra Hernandez, Mary Van Akin, Molly Ellis, and Brittany Pearlman.

Monique Sterling from Macmillan Children’s art department as Tallulah from Tallulah the Tooth Fairy CEO by Tamara Pizzoli.

(From l.): John Morgan, Jessica Chung, and Erin Stein of Imprint as characters from Snazzy Cat Capers by Deanna Kent.

Jon Anderson (r.), president and publisher of Simon Schuster Children’s Publishing, as Jane Goodall; and Richard Ackoon as Neil deGrasse Tyson from This Little Scientist by Joan Holub, illustrated by Daniel Roode.

Members of the Atheneum/McElderry/Beach Lane design department channeled Skulls! by Blair Thornburgh, illustrated by Scott Campbell.

The SS costume winners with hosts Anderson and Ackoon.

The sales department at Scholastic looking sharp as Baby Shark.

Scholastic costume contest judge R.L Stine with v-p of trade communications, publicity, and educational marketing Tracy van Straaten as Slappy.

The Scholastic licensing team as characters from Overwatch.

Something wicked comes to Little, Brown: (from l.) associate art director for marketing and communications Becky Munich, graphic designer Joanne Campbell, and associate director of creative services Nisha Panchal-Terhune as the witches from Zip! Zoom! On a Broom by Teri Sloat, illustrated by Rosalinde Bonnet.

(From l.): Michelle Campbell, senior school and library marketing manager at Little, Brown, and school and library marketing coordinator Christie Michel as the Pirate and Santa from Elise Parsley’s forthcoming picture book, If You Ever Want to Bring a Pirate to Meet Santa, Don’t!

Disney staffers paid homage to We Don’t Eat Our Classmates by Ryan T. Higgins: (from l.) Laura Schreiber, Elke Villa, Emily Meehan, and Dina Sherman.

The editorial and copy editing staff at Disney as Mo Willems’s Unlimited Squirrels.

Quarto went back to the future for an ’80s movie party.

The staff at Magination Press dressed as characters from some of their titles, including Bentley from Bee Still, Kiko from Grow Happy, and Robot from Box of Butterflies.

Charlesbridge got in the Halloween spirit.

Sterling Children’s Books conjured up an assortment of sweet treats. (From l.): Kate Zimmerman, Nicole Fisher, Sari Murray, and Sharmilla Sinanan.

The collection development and merchandising team at First Book wore costumes inspired by Stegothesaurus by Bridget Heos, illustrated by T.L. McBeth. (From l.): Blake Kaiser-Lack, Lori Prince, Alison Morris, Yukari Matsuyama, and Jack Pando.