Mark Oestreicher (Marko) is the president of Youth Specialties and a life-long youth worker. He has worked with middle schoolers for about 25 years, both as a paid and a volunteer youth worker. Marko has written dozens of books for students and youth workers and speaks to thousands around the world each year. Mark Oestreicher. Presidente de Jovenes especializados. Mark ha contribullido en escribir serca de 30 libros en el ministerio juvenil, incluyendo los libros mejor vendidos desde el principio de esta serie. Dos volumenes de Verdad Desenfrenada Diario para Juniors y Middle Schoolers y cuatro volumenes Verdad Desenfrenada Lecciones de la Biblia. Y esta publicada en muchas revistas. Marko tambien mantiene un horario bien pesado de hablantes a adolecentes y adultos en los Estados Unidos. El vive en El Cajon, California con su esposa y dos hijos. Scott Rubin has been on staff at Willow Creek Community Church for 15 years, and he's currently the director of Elevate, the junior high ministry at Willow Creek. Scott, along with a partially-peculiar, entirely-fantastic team of staff and volunteer leaders, has the privilege of helping junior high students follow Jesus together. He also co-authored two books in the Middle School Survival Series with Mark Oestreicher.