The ESL-Grammar Explorer 1 by Daphne Mackey is a grammar book published by National Geographic Learning/Cengage Learning in 2015. It focuses on English language teaching and covers various aspects of English grammar. Written in English, this book is designed for language study and provides students with a comprehensive understanding of grammar rules and concepts. The author, Daphne Mackey, is a recognized expert in the field of English language teaching, making this book a valuable resource for learners looking to improve their grammar skills.