  We characterize the ground state and excitation spectrum of the $S=1/2$,
nominally pure and perfect kagom\'{e} system ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$ using
the following measurements: magnetization, muon spin rotation frequency shift
$K$, transverse relaxation time $T_{2}^{\ast}$, and zero field relaxation, and
Cl nuclear spin-lattice relaxation $T_{1}$. We found no sign of singlet
formation, no long range order or spin freezing, and no sign of spin-Peierls
transition even at temperatures as low as 60 mK. The density of states has
$E^{1/4}$ energy dependence with a negligible gap to excitation.
