  We have derived the most general chirally invariant Lagrangian ${\cal L}_6$
for the meson sector at order $p^6$. The result provides an extension of the
standard Gasser-Leutwyler Lagrangian ${\cal L}_4$ to one higher order,
including as well all the odd intrinsic parity terms in the Lagrangian. The
most difficult part of the derivation was developing a systematic strategy so
as to get all of the independent terms and eliminate the redundant ones in an
efficient way. The 'equation of motion' terms, which are redundant in the sense
that they can be transformed away via field transformations, are separated out
explicitly. The resulting Lagrangian has been separated into groupings of terms
contributing to increasingly more complicated processes, so that one does not
have to deal with the full result when calculating $p^6$ contributions to
simple processes.
