  $\rm CePt_3Si$ is a novel ternary compound exhibiting antiferromagnetic order
at $T_N \approx 2.2$ K and superconductivity (SC) at $T_c \approx 0.75$ K.
Large values of $H_{c2}' \approx -8.5$ T/K and $H_{c2}(0) \approx 5$ T indicate
Cooper pairs formed out of heavy quasiparticles. The mass enhancement
originates from Kondo interaction with a characteristic temperature $T_K
\approx 8$ K. NMR and $\mu$SR measurements evidence coexistence of SC and long
range magnetic order on a microscopic scale. Moreover, $\rm CePt_3Si$ is the
first heavy fermion SC without an inversion symmetry. This gives rise to a
novel type of the NMR relaxation rate $1/T_1$ which is very unique and never
reported before for other heavy fermion superconductors. Studies of Si/Ge
substitution allow us to establish a phase diagram.
