  Path integrals don't really exist, but it is very useful to dream that they
do exist, and figure out the consequences. Apart from describing much of the
physical world as we now know it, these dreams also lead to some highly
non-trivial mathematical theorems and theories. We argue that even though
non-trivial flat connections on S^3 don't really exist, it is beneficial to
dream that one exists (and, in fact, that it comes from the non-existent
Chern-Simons path integral). Dreaming the right way, we are led to a rigorous
construction of a universal finite-type invariant of rational homology spheres.
We show that this invariant is equal to the LMO (Le-Murakami-Ohtsuki) invariant
and that it recovers the Rozansky and Ohtsuki invariants.
  This is part I of a 4-part series, containing the introductions and answers
to some frequently asked questions. Theorems are stated but not proved in this
part, and it can be viewed as a "research announcement". Part II of this series
is titled "Invariance and Universality" (see math/9801049), part III "The
Relation with the Le-Murakami-Ohtsuki Invariant" (see math/9808013), and part
IV "The Relation with the Rozansky and Ohtsuki Invariants".
