  We review some recent developments in the study of M-theory compactifications
via Matrix theory. In particular we highlight the appearance of IIA strings and
their interactions, and explain the unifying role of the M-theory five-brane
for describing the spectrum of the T^5 compactification and its duality
symmetries. The 5+1-dimensional micro-string theory that lives on the fivebrane
world-volume takes a central place in this presentation.
