Is it possible to pass your Series 7 exam without reading a textbook? Of course. Is it probable? Of course not. A well organized and written textbook will contain the many details you'll need to be familiar with and introduce you to all the vocabulary terms the test will expect you to know.
But, really, the key to passing the Series 7 exam is to take and learn from a good set of practice questions. I don't mean that you should simply bang out questions and track your score. I mean, you need to use the practice questions to learn the material. For example, our Pass the 7 ExamCram Online Test Prep provides a helpful rationale to each question so that you can LEARN as you improve your testing skills. Take notes on these rationale. Try to imagine the many variations that could be written on this question.
First time I took the Series 65 I did nothing but practice questions--I simply popped in the CD (hey, it was the early 2000's), expected to miss the questions first time through, then took notes based on the rationale. Of course, I was already a Series 7 and 63 instructor, so that was a perfectly fine way for me to study. For most people, the process should probably involve reading the textbook chapter-by-chapter. After each chapter, take the associated quizzes in ExamCram and--again--take notes based on the rationale. If you have the DVD set, watch the corresponding sessions now, and you will be amazed at how well you suddenly know options, bond yields, DPPs, what have you. Once you've read the book and done the section quizzes, move onto the practice finals, trying to get at least a 75%.