Supersymmetry at the Linear Collider

If supersymmetry (SUSY) is realized at the electroweak scale, its underlying structure and breaking mechanism may be explored with great precision by a future linear $e^+ e^-$ collider (LC) with a clean environment, tunable collision energy, high luminosity polarized beams, and additional $e^-e^-$, $e\gamma$ and $\gamma\gamma$ modes. In this report we summarize four papers submitted to the ICHEP04 conference about the precise measurements of the top squark parameters and $\tan\beta$, the impacts of the CP phases on the search for top/bottom squarks, the Majorana nature and CP violation in the neutralino system, the implications of the SUSY dark matter scenario for the LC experiments, and the characteristics of the neutralino sector of the next--to--minimal supersymmetric standard model at the LC