  We review our proposal for a constructive definition of superstring, type IIB
matrix model. The IIB matrix model is a manifestly covariant model for
space-time and matter which possesses N=2 supersymmetry in ten dimensions. We
refine our arguments to reproduce string perturbation theory based on the loop
equations. We emphasize that the space-time is dynamically determined from the
eigenvalue distributions of the matrices. We also explain how matter, gauge
fields and gravitation appear as fluctuations around dynamically determined
space-time.
