  We review and extend the description of ultradifferentiable functions by
their almost analytic extensions, i.e., extensions to the complex domain with
specific vanishing rate of the $\bar \partial$-derivative near the real domain.
We work in a general uniform framework which comprises the main classical
ultradifferentiable classes but also allows to treat unions and intersections
of such. The second part of the paper is devoted to applications in microlocal
analysis. The ultradifferentiable wave front set is defined in this general
setting and characterized in terms of almost analytic extensions and of the FBI
transform. This allows to extend its definition to ultradifferentiable
manifolds. We also discuss ultradifferentiable versions of the elliptic
regularity theorem and obtain a general quasianalytic Holmgren uniqueness
theorem.
