Mario Herrera has a degree in education and an MA in EFL. He has taught English for more than 25 years at all levels, from young children to adults. He is the co-author of seven ESL/EFL series that are used in levels ranging from preprimary to junior high. He co-authored "Balloons," His latest series is "Backpack," a seven-level primary EFL series. As an international consultant and teacher trainer, Mr. Herrera travels on behalf of Pearson Education, directing seminars and performing in-service training sessions throughout the Americas, Europe, the Middle East, and Asia. Barbara Hojel has an MA in education from Johns Hopkins University and 34 years' experience teaching very young children and training teachers. As an educational consultant, she has led workshops and seminars throughout Mexico and Central and South America. She has also trained teachers in Japan and the United States.