The book is organized into chapters, where each chapter lets you exercise different skills in a given tense; then the chapters on mixed tenses, infinitives, and participles follow, with the answers to all exercises at the end. Please note that this is mainly an exercise book and there is only a bare minimum of the theory, so you would probably get the most out of it if it was used in combination with grammar guide of the same series. Also, I used the PDF version, and switching between exercises and answers is a bit cumbersome, so I would recommend getting an e-book version instead with links to the answers and back to the questions. All in all, this book would be a great help to teachers, writers, intermediate and advanced learners, and all language users who want to brush up on the correct use of grammar.