  Multiscale modeling of material properties has emerged as one of the grand
challenges in material science and engineering. We provide a comprehensive,
though not exhaustive, overview of the current status of multiscale simulations
of materials. We categorize the different approaches in the spatial regime into
sequential and concurrent, and we discuss in some detail representative methods
in each category. We classify the multiscale modeling approaches that deal with
the temporal scale into three different categories, and we discuss
representative methods pertaining to the each of these categories. Finally, we
offer some views on the strength and weakness of the multiscale approaches that
are discussed, and touch upon some of the challenging multiscale modeling
problems that need to be addressed in the future.
