Considering that many (all?) of the ideas presented in Dr. B's book are age-old, tried and true... no, I think you need not be concerned in the least about them being 'outdated'. I also happen to know Dr. B and have been treated by him on occasion, as a child (at the 'tute -- the same place where this book was published, actually). He knows his stuff. So there you go, a personal testimony, even.