  In ballistic deposition (BD), $(d+1)$-dimensional particles fall sequentially
at random towards an initially flat, large but bounded $d$-dimensional surface,
and each particle sticks to the first point of contact. For both lattice and
continuum BD, a law of large numbers in the thermodynamic limit establishes
convergence of the mean height and surface width of the interface to constants
$h(t)$ and $w(t)$, respectively, depending on time $t$. We show that $h(t)$ is
asymptotically linear in $t$, while $w(t)$ grows at least logarithmically in
$t$ when $d=1$. We also give duality results saying that the height above the
origin for deposition onto an initially flat surface is equidistributed with
the maximum height for deposition onto a surface growing from a single site.
