  Today there are a plethora of many-body techniques for calculating nuclear
wave functions and matrix elements. I review the status of that reliable
workhorse, the interacting shell model, a.k.a. configuration-interaction
methods, a.k.a. Hamiltonian diagonalization, and survey its advantages and
disadvantages. With modern supercomputers one can tackle dimensions up to about
20 billion! I discuss how we got there and where we might go in the near
future.
