Kaplan Premier is an awesome book to start preparation with. This book have enough questions as well as the strategies to attack the question. This book helped me a lot in the verbal part and the best thing is that this comes with 5 free tests. The tests provide very good replica of you preparation. Many people argue that hose tests are not close to the real GMAT but at the end the real mark is +-20 of what you scored in the Kaplan tests so i believe we can rely on the same. Also the tests are very user friendly and the explanation of questions are very helpful.