Kate Prosswimmer

Kate Prosswimmer – Editor

Children's book editor of multiple NYT bestsellers (PB, MG, and YA) with 10+ years of experience - let me help you optimize your story!

Overview

I was lucky enough to join the publishing world 11 years ago when I began interning for The Bent Agency, where I learned how to make a living doing what I love: helping create amazing books!

After completing my Master’s degree in English Lit and working part-time at TBA, I started at Sourcebooks in Children’s Editorial where I discovered my passion for editing. There’s nothing quite like working with the world’s most creative people to help take their inspired creations to the next level! During my almost six years at Sourcebooks, I had the chance to work on incredible projects like Zoraida Cordova’s critically acclaimed BROOKLYN BRUJAS series; Jess Keating’s award-winning picture book, SHARK LADY; and Jen Calonita’s enchanting and hilarious FAIRY TALE REFORM SCHOOL series. I am now a Senior Editor at Simon & Schuster, where I've acquired an exciting new list of bestselling and award-winning titles, including Amanda Foody's WILDERLORE series, SPELL BOUND and SO THIS IS EVER AFTER by F.T. Lukens, NOODLE AND THE NO BONES DAY by Jonathan Graziano and Dan Tavis, and A DOOR IN THE DARK by Scott Reintgen.

I’ve edited a wide variety of projects from picture books through YA. I love the whole spectrum of contemporary to speculative, though I’m not the best fit for graphic novels or novels in verse. I also routinely attend conferences with SCBWI and other organizations where I teach workshops and provide critiques. In short, I love books and reading!!

Services
Fiction
Middle Grade Middle Grade Fantasy Young Adult
Languages
English (US)
Certifications
  • Master’s Degree in English Literature

Work experience

Simon & Schuster

Apr, 2019 — Present
Acquires, edits, positions, and oversees the publication process for a list of picture books, middle grade, and young adult projects for each season.

Sourcebooks

Sep, 2013 — Apr, 2019 (over 5 years)
Acquires, edits, positions, and oversees the publication process for a list of picture books, middle grade, and young adult projects for each season.

The Bent Agency

Jun, 2013 — Aug, 2013 (2 months)
Provided support cataloging contracts, reviewing manuscripts, and evaluating query letters.

Portfolio

The Accidental Apprentice (1) (Wilderlore)

Foody, Amanda

Margaret K. McElderry Books

The Dagger and the Flame (The City of Fantome)

Doyle, Catherine

Margaret K. McElderry Books

It's Almost Time for . . . Halloween!

Oso, Maisha

Margaret K. McElderry Books

Best Buds

Scharnhorst, Becky

Margaret K. McElderry Books

Grown with Love

Wicker, Valeria

Margaret K. McElderry Books

Falling Like Leaves (Bramble Falls)

Wilson, Misty

Margaret K. McElderry Books

The Tournament

Barrow, Rebecca

Margaret K. McElderry Books

The House at the Edge of Magic

Sparkes, Amy

Walker Books

Tangled Up in Luck (1) (The Tangled Mysteries)

Wyatt, Merrill

Margaret K. McElderry Books

And Don't Look Back

Barrow, Rebecca

Margaret K. McElderry Books

Those Summer Nights

Silverman, Laura

In Deeper Waters

Lukens, F.T.

Bad Things Happen Here

Barrow, Rebecca

An Amazon Best Book of the Month―Named a Best Children's Book of 2017 by Parents magazine―One of New York Times's Twelve Books for Feminist Boys and Girls! Discover the story of a woman who dared to dive, defy, and inspire. This is Shark Lady.Learning about sh... read more
Recommended for You

Silverman, Laura

Lies Like Poison

Pitcher, Chelsea

The only way to get her family back is to travel to a land in between, as dark as Limbo and as strange as Wonderland...Alex is a bruja, the most powerful witch in a generation...and she hates magic. At her Deathday celebration, Alex performs a spell to rid her... read more
"Funny, charming, and rebellious." -James Riley, New York Times bestselling author of The Story Thieves series and the Revenge of Magic seriesIn Enchantasia, becoming a legendary prince or princess doesn't happen overnight. Enter Royal Academy, the training gr... read more
I Love Kisses

Sheryl McFarlane

I love kisses. I'll bet that you do too!Wake up sleepyhead kissesRaspberry jam and bread kisses... There are lots of kinds of kisses in the world, and they all say something different. Award-winning author Sheryl McFarlane's new book celebrates the best part a... read more

Kate has 23 reviews

Professionalism

Quality

Value

Responsiveness

Ellen B.

Ellen B.

Mar, 2025

Pinned
Kate's feedback was exactly what I was looking for - clear and professional and insightful! I chose Kate because of her love for and experience with middle grade fiction and she brought the exact expertise I was looking for. I feel like I have a good sense of how to move forward with my manuscrip...
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Mark C.

Mark C.

Oct, 2023

Pinned
Kate always does fantastic work for me. Her editorial eye is sharp and her ability to help me craft the story in deeper ways is always a benefit; that's why I keep going back to her . . . you should too!
Mark H.

Mark H.

Jun, 2023

Pinned
I hired Kate for a developmental edit on an MG novel that I knew needed help but I couldn't see how. Kate gave a very clear editorial assessment - as well as line notes on the manuscript - that provided what beta readers couldn't - a roadmap to follow for this next rewrite. Her edits focused on t...
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Steven F.

Steven F.

Sep, 2025

Kate has really helped with character development, motivation, arc, etc. She has been a great help and my story has really grown in such a short time.
Bassem S.

Bassem S.

Jul, 2025

Kate did an amazing job breaking down the good, the bad, and the ugly and pointing me in clearly defined directions for my revisions. She delivered the editorial assessment on time which surprised me considering the length of my book and the detailed feedback she was able to provide.

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