This program is absolutely superior, effective, and empowering. I hesitated to answer this survey question asking if I used other study materials because I did look at other materials but I did not use them. Once I was involved in TDC's program, I just looked at other materials and found them incredibly confusing, disempowering, and sometimes featuring plain wrong information!! I decided to place my trust on TDC alone and it worked. I cannot say enough great things about TDC and could not recommend it more highly. I believe in the program so much that, if I could, I would work for TDC.