This used book is in Like New condition. Jensen's Grammar lessons and exercises were built with three concepts in mind. First, spaced repetition is the key to learning; hence, there is review in every lesson. Second, the information is given incrementally; that is, the material comes in a natural progression of detail and concept interwoven so as to move you along with something new each lesson while fitting it in with the material previously learned and practiced. Third, the sentences in the exercises will generally set a scene or describe an action. Thus, they are usually more interesting reading in themselves instead of the random sentences in exercises found in most grammar texts.