  Layered structure of Bi-2212 high $T_c$ superconductor (HTSC), provides a
unique opportunity to probe quasiparticle density of states inside a bulk
single crystal by means of intrinsic (interlayer) tunneling spectroscopy. Here
I present a systematic study of intrinsic tunneling characteristics of Bi-2212
as a function of doping, temperature, magnetic field and intercalation. An
improved resolution made it possible to simultaneously trace the
superconducting gap (SG) and the normal state pseudo-gap (PG) in a close
vicinity of $T_c$ and to analyze closing of the PG at $T^*$. The obtained
doping phase diagram exhibits a critical doping point for appearance of the PG
and a characteristic crossing of the SG and the PG close to the optimal doping.
All this points towards coexistence of two different and competing order
parameters in Bi-2212.
