Teaching adults is a very different task from teaching children, requiring a wholly separate approach. I feel especially qualified to teach adults, because I did most of my own learning as an adult. Since I have traveled the path of learning an instrument as on older beginner, I am very well situated to help others on that same path. My approach will provide you with new insights even if you are not a beginner, but are looking to take your playing to the next level and overcome the technical barriers you might be facing.
For anyone who has the desire to play piano, but feels like it may be "too late," I say, "Let's get started!" The piano is surrounded by a reputation that one must begin as a small child in order to see real achievement. Modern neuroscience regarding brain plasticity says otherwise. It will require patience, discipline, and consistent practice, but beginners of any age can make great progress. In fact, I believe that adults can even learn faster than children! Make the time for your instrument, and results will come.
For older students in particular, I am not attached to any one set of method books. Methods are a wonderful way to structure lessons. However, it is important for me to note that I do not teach straight from any book in particular, but draw on the vast set of repertoire and exercises that are available for the piano. In this way, I can tailor my teaching to the needs and interests of each student.
For an older student, by which I mean fourteen and up, I recommend no less than one 60 minute lesson per week. That time will go by quickly, and there are many elements that go into creating a well rounded musician. The more time we have together, the better!