Sentinel
Overview
Sentinel is an imprint of Penguin Random House, the world’s largest trade book publisher. Founded in 2003, we are an established publisher of critically acclaimed and bestselling nonfiction. Our mission is to provide a home for independent-minded thinkers and storytellers who challenge mainstream opinion, whether by looking to the past or reimagining the future.
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Meet the Team
Adrian Zackheim, Founder, President, and Publisher
Adrian joined Penguin Group in September 2001 as founder and publisher of Portfolio. He then took on the additional challenge of starting Sentinel in April 2003. In 2018, he announced the addition of another new imprint to the group: The Optimism Press, in collaboration with Simon Sinek.
Previously, he was the associate publisher and editor-in-chief of HarperInformation, a division of HarperCollins that included HarperBusiness. His editorial career has also included positions at William Morrow, Doubleday, and St. Martin’s Press, and his first job was as school and library publicity assistant at G. P. Putnam’s Sons, which was then a privately held small publishing company. He later moved to Putnam’s editorial department under the leadership of Editor-in-Chief Phyllis Grann.
Among the many bestselling books he edited and published before joining Penguin Group were Good to Great by Jim Collins; Die Broke by Stephen Pollan and Mark Levine; The Dilbert Principle by Scott Adams; The HP Way by David Packard; and Swim with the Sharks without Being Eaten Alive by Harvey Mackay.
Margot Stamas, Associate Publisher and Director of Publicity and Marketing
Margot joined Portfolio in 2012. As the associate publisher and director of publicity and marketing, Margot is responsible for overseeing the promotional strategy across the Portfolio, Sentinel, and Optimism Press lists. She has led bestselling campaigns for Sophia Amoruso’s #GIRLBOSS, Marie Forleo’s Everything Is Figureoutable, Cal Newport’s Digital Minimalism, Emily Chang’s Brotopia, Gregory Zuckerman’s The Man Who Solved the Market, and more.
Bria Sandford, Executive Editor
Bria joined Portfolio and Sentinel in 2012 and helped launch Thesis in 2022. Her critically acclaimed and bestselling authors include Oprah Winfrey, Arthur Brooks, Peggy Noonan, Abigail Shrier, Christine Emba, Nellie Bowles, John McWhorter, and Brian Kilmeade.
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Helen Healey-Cunningham, Executive Editor
Since joining Portfolio and Sentinel in 2017, Helen has acquired and edited eight New York Times bestsellers. She gets excited about idea-driven books that offer bold new ways to see the world, especially books that warn of looming dangers, make provocative arguments, meditate on serious issues, and inspire positive change. She has edited a diverse cast of experts, from survivalists and evolutionary psychologists to clinical psychologists, activists, philosophers, and CIA analysts.
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Megan Wenerstrom, Associate Editor
Megan joined Sentinel in 2022, drawn to big ideas that push boundaries and inspire new perspectives. Her authors span a diverse range of thinkers—entrepreneurs, philosophers, environmentalists, tech experts, activists, and even cowboys —bringing fresh insights to readers. Before publishing, Megan’s career began as a public school teacher, where she cultivated her talent for sparking curiosity and meaningful dialogue.
Kelly Young, Editorial Assistant
Kelly Young joined Portfolio, Thesis, and Sentinel as an Editorial Assistant in 2025. She is drawn to practical, insightful nonfiction that challenges conventional thought and sparks new ideas and ways of living. Before joining Portfolio, Kelly started her career as a copyeditor, which cemented her passion for working with innovative books that inspire readers.
Amanda Lang, Publicity Director
Amanda joined the Portfolio team in 2020. She oversees media strategy for the imprint and an immensely talented team of publicists. She has worked on many bestselling and high-profile campaigns for authors including Arthur Brooks and Oprah Winfrey, Peggy Noonan, John McWhorter, Cal Newport, Nellie Bowles, Coleman Hughes, Annie Duke, Matthew Yglesias, Bethany McLean and Joe Nocera, and more.
Stefanie Rosenblum Brody, Executive Publicist
Stefanie joined Portfolio in 2013. Over the last decade she has led campaigns for notable authors such as Ryan Holiday, Morgan Housel, Katy Milkman, Jennifer Breheny Wallace, and others. She is passionate about working closely with authors to develop strategic publicity campaigns that leverage their platforms, grow their communities, and help their books find new audiences. She is originally from Los Angeles and has a BA in English from Wheaton College Massachusetts.
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Kirstin Berndt, Senior Publicity Manager
Kirstin joined Penguin Random House in 2021. As senior publicity manager, Kirstin has led bestselling campaigns for the #1 New York Times bestseller The Algebra of Wealth, Power Failure, Unreasonable Hospitality, and more. Previously, she worked with an impressive range of authors, including David Rubenstein, Lulu Miller, Twyla Tharp, and Sebastian Junger. Before her career in publishing, Kirstin spent several years working for the US Army.
Heather Faulls, Senior Marketing Manager
Heather joined Portfolio and Thesis in 2021, bringing over a decade of experience in publishing and digital marketing. She specializes in driving engagement and sales through strategic, story-driven campaigns that elevate brand narratives and connect with audiences. Heather has led several New York Times bestselling campaigns, including for The Algebra of Wealth and Wild Courage. She also oversees Portfolio’s social media presence and influencer program, managing a talented team to expand reach and deliver measurable impact.
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Lauren Ball, Senior Publicist
Lauren joined Portfolio in January 2023 after working in the self-publishing and music industries. She is passionate about discovering ways to connect books with their readers and has worked with multiple New York Times bestselling titles including Ethan Mollick’s Co-Intelligence and Vivian Tu’s Rich AF.
Jackie Galindo, Marketing Associate
Jackie joined Portfolio in May 2022, bringing a robust background in digital marketing and a vibrant Texan spirit. A UT Austin graduate, she honed her skills at the University of Texas Press, working with a diverse range of books. Passionate about diverse, thought-provoking titles, Jackie has played a key role in propelling New York Times bestsellers like Never Enough and Rich AF to new heights. She also manages Portfolio’s monthly influencer program, collaborating closely with the marketing team to bring our titles to new audiences through bookstagrammer support.
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Savana Bishop, Marketing Associate
Savana joined Portfolio in May 2022 and brings a passion for connecting readers to books they’ll love. She enjoys championing bold, idea-driven books that challenge and inspire. Savana has worked with a diverse group of authors including John Lovell, Coleman Hughes, Edward Fishman, and Tessa West. She recently led marketing efforts for the instant #1 New York Times bestselling The Small and the Mighty. Savana is a proud Clemson University graduate, and when she’s not working on books, she’s reading them.
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Taylor Williams, Publicity Associate
Taylor joined Portfolio as a publicity assistant in June 2022. She has a passion for working on books written to improve both our professional and personal lives, amplify marginalized and underrepresented voices, and offer new ways to see the world. Since starting at Portfolio, she’s worked on New York Times bestsellers including Build the Life You Want by Arthur C. Brooks and Oprah Winfrey and Rich AF by Vivian Tu. She graduated from the University of Southern California Annenberg School for Communication and Journalism with a MA in public relations and advertising.
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Bridget Sjoberg, Marketing Assistant
Bridget joined Portfolio in 2023 after graduating with an MA in English literature from New York University. She loves to help craft pre-order initiatives that are specific to each author’s unique audience, and she enjoys handling social media engagement and influencer analytics for the imprint. Bridget is interested in books featuring unconventional success stories, psychology, religion, and the environment. She has assisted on the campaigns of three New York Times bestsellers— Million Dollar Weekend by Noah Kagan, Co-Intelligence by Ethan Mollick, and Morning After the Revolution by Nellie Bowles.
Bridget's Featured Titles
Daniel Marx, Publicity Assistant
Daniel joined the Portfolio, Sentinel, Optimism Press, and Thesis imprints as a publicity assistant in 2024. With a particular interest in nonfiction, Daniel loves working on titles that explore themes of race, class, global politics, and economics. Prior to joining the publicity team, Daniel taught English in Paris and earned a master’s degree from Montclair State University.
Catherine Morrissette, Publicity Assistant
Catherine joined Portfolio in 2024 as a publicity assistant. She is passionate about books that challenge the status quo and encourage readers to think beyond themselves, and subject matters related to international affairs, business, psychology, and technology. Originally from Maine, she completed the Columbia Publishing Course and graduated from Brown University with degrees in English nonfiction and political science.