  A massive envelope and a strong bipolar outflow are the two main structures
characterizing the youngest protostellar systems. In order to understand the
physical properties of a bipolar outflow and the relationship with those of the
envelope, we obtained a mosaic map covering the whole bipolar outflow of the
youngest protostellar system L1157 with about $5"$ angular resolution in CO
J=2-1 using the Combined Array for Research in Millimeter-wave Astronomy. By
utilizing these observations of the whole bipolar outflow, we estimate its
physical properties and show that they are consistent with multiple jets. We
also constrain a preferred precession direction. In addition, we observed the
central envelope structure with $2"$ resolution in the $\lambda=1.3$ and 3 mm
continua and various molecular lines: C$^{17}$O, C$^{18}$O, $^{13}$CO, CS, CN,
N$_2$H$^+$, CH$_3$OH, H$_2$O, SO, and SO$_2$. All the CO isotopes and CS, CN,
and N$_2$H$^+$ have been detected and imaged. We marginally detected the
features that can be interpreted as a rotating inner envelope in C$^{17}$O and
C$^{18}$O and as an infalling outer envelope in N$_2$H$^+$. We also estimated
the envelope and central protostellar masses and found that the dust opacity
spectral index changes with radius.
