  Aberration-corrected electron microscopy can resolve the smallest atomic
bond-lengths in nature. However, the high-convergence angles that enable
spectacular resolution in 2D have unknown 3D resolution limits for all but the
smallest objects ($< \sim$8nm). We show aberration-corrected electron
tomography offers new limits for 3D imaging by measuring several focal planes
at each specimen tilt. We present a theoretical foundation for
aberration-corrected electron tomography by establishing analytic descriptions
for resolution, sampling, object size, and dose---with direct analogy to the
Crowther-Klug criterion. Remarkably, aberration-corrected scanning transmission
electron tomography can measure complete 3D specimen structure of unbounded
object sizes up to a specified cutoff resolution. This breaks the established
Crowther limit when tilt increments are twice the convergence angle or smaller.
Unprecedented 3D resolution is achievable across large objects. Atomic 3D
imaging (1$\unicode{xC5}$) is allowed across extended objects larger than
depth-of-focus (e.g. $>$ 20nm) using available microscopes and modest specimen
tilting ($<$ 3$^\circ$). Furthermore, aberration-corrected tomography follows
the rule of dose-fractionation where a specified total dose can be divided
among tilts and defoci.
