Barron’s ESL Proficiency Series: Prepositions provides comprehensive coverage of this most difficult topic in English grammar. The idiosyncratic nature of prepositions often makes them a barrier to achieving English language proficiency. Jean Yates offers clear explanations with lots of examples and opportunities to practice.  Content is organized into simple 15-minute units each of which has its own practice exercises. An answer key is included in the back of the book.  The ESL Profiency Series is a valuable tool for ESL teachers, tutors and learners who want to advance their English language skills for work, school or to prepare for proficiency tests such as TOEFL, IELTS,  or TOEIC. It is ideal for independent study.