The "Gateway to Arabic" series is a well-structured, progressive course that has been designed to teach Arabic to non-Arabic-speakers from a broad age range. As students progress in building up their knowledge of Arabic grammar and vocabulary, they are able to put into practice the skills they have acquired through written drills, spoken passages of dialogue and comprehension exercises. "Gateway to Arabic Book Four" builds upon the knowledge of first form regular past and present tense verbs acquired in Book Three of the series, by introducing the student to the concept of first form hollow, doubled root letter and hamzated verb forms. It also further develops the student's knowledge of ordinal and cardinal numbers and the rules governing them, and teaches the use of numbers in telling the time as well as for counting.