  The Super $\tau$-Charm facility (STCF) is an electron-positron collider
proposed by the Chinese particle physics community. It is designed to operate
in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of
$0.5\times 10^{35}{\rm cm}^{-2}{\rm s}^{-1}$ or higher. The STCF will produce a
data sample about a factor of 100 larger than that by the present $\tau$-Charm
factory -- the BEPCII, providing a unique platform for exploring the asymmetry
of matter-antimatter (charge-parity violation), in-depth studies of the
internal structure of hadrons and the nature of non-perturbative strong
interactions, as well as searching for exotic hadrons and physics beyond the
Standard Model. The STCF project in China is under development with an
extensive R\&D program. This document presents the physics opportunities at the
STCF, describes conceptual designs of the STCF detector system, and discusses
future plans for detector R\&D and physics case studies.
