  High temperature superconductivity in cuprate superconductors remains an
unsolved problem in theoretical physics. The same statement can also be made
about a number of other superconductors that have been dubbed unconventional.
What makes these superconductors so elusive is an interesting question in
itself. The present manuscript focuses on the recent magnetic oscillation
experiments and how they fit into the broader picture. Many aspects of these
experiments can be explained by Fermi liquid theory; the key issue is the
extent to which this is true. If true, the entire paradigm developed over the
past three decades must be reexamined. A critical analysis of this issue has
necessitated a broader analysis of questions about distinct ground states of
matter, which may be useful in understanding other unconventional
superconductors.
