  We first briefly survey the value-distribution theory of L-functions of the
Bohr-Jessen flavor (or the theory of "M-functions"). Limit formulas for the
Riemann zeta-function, Dirichlet L-functions, automorphic L-functions etc. are
discussed. Then we prove new results on the value-distribution of symmetric
power L-functions, which are limit formulas involving associated M-functions.
