Who We Are

Our team includes a diverse array of publishing and instructional design professionals with decades of experience.

Doug Seibold, president, has worked in trade, educational, and nonprofit publishing and media for the past 35 years. From 1999 to 2002, he was the founding editorial director of UNext, which created online schools in partnership with universities such as Stanford, Columbia, and the University of Chicago. He founded Agate Publishing in 2003 and started Agate Development in 2005.

Suzanne Sonnier, vice president of content development, has over 20 years of experience in education and educational publishing and is a former middle school, high school, university, and community college instructor. She holds an MA in History and is the author of Shinto, Spirits, and Shrines: Religion in Japan and A Sunny Spot for Mateo and Blanca, and has developed many K-12 and college textbooks, supplements, and standardized assessments, as well as adult education and trade book content. She joined Agate in 2011.

Erin Rosenberg, senior director of content development, began her career as a classroom teacher and has more than 20 years of experience in curriculum development and assessment creation. She holds a Master’s degree in Education and has worked as a writer, editor, and project lead on a wide variety of digital and print products for K-12 students and teachers. She joined Agate in 2021.

David Schlesinger, director of content development, has 15 years of experience in publishing and education. He has worked as a writer, editor, instructional designer, and project manager to develop trade books, textbooks, and a variety of educational materials intended for primary grades through higher education. In recent years, he has worked mostly with continuing professional education and corporate partners to develop digital and print publications as well as custom online courses. He joined Agate in 2011.

Katie Jones-Aiello, director of content development, has worked in publishing and content development for 16 years. Her career has focused on textbook and digital publishing offerings for higher education and nonprofits, as well as copyediting, writing, and editorial work for K-12 and higher ed. Previously, she worked for eight years with McGraw Hill Education as a product developer. She began her career as an intern with Agate Publishing in 2004 and rejoined Agate in 2019.

Marta Evans, associate director of content development, has 15 years of experience in publishing, writing education, and education support services. She has a graduate degree in writing and is a former university instructor. She has also worked as a writer, editor, instructional designer, and project manager to develop trade books and a variety of educational materials, as well as publications and online courses for corporate and continuing education partners. She began her career with Agate Publishing in 2006 and rejoined Agate in 2016.