 The book expands upon the classical conceptions of work and information in order to give an account of ententionality that is consistent with eliminative materialism and yet does not seek to explain away or pass off as epiphenominal the non-physical properties of life.A central thesis of the book is that absence can still be efficacious.Deacon makes the claim that just as the concept of zero revolutionized mathematics, thinking about life, mind, and other ententional phenomena in terms of constraints (i.e., what is absent) can similarly help us overcome the artificial dichotomy of the mind body problem.