The only application of string theory mentioned in public synopses of the book is "superstring theory applied to the quantum mechanics of neurons". Now, shortly after Roger Penrose and Stuart Hameroff came out with their theory of consciousness, according to which Penrose's gravity-driven wavefunction collapse is at work in neuronal microtubules, two particle physicists working with string theory (Nick Mavromatos and Dmitri Nanopoulos) came out with their own model, treating microtubules as "non-critical strings". It's very very likely that this is what the book talks about.

Meanwhile, with respect to supersymmetry in general, it does have a number of surprising applications outside of particle physics, for example in random systems. I have a particular interest in possible applications to machine learning, a concept I first ran across on this very site.

The book is **not at all crackpot.** But it looks hastily assembled, and I'm not sure how well the author actually understands the advanced theory. Most of his publications are in signal processing. I think he's put together the exotic applications of supersymmetry that interest him, and then he's tried to write a basic exposition of all the supersymmetric theory he uses too, to make the book self-contained. But anyone really trying to study the theory from this, should keep a proper textbook or review at hand, as well.