  The most compelling and popular models for dark matter predict that it should
congregate and annihilate in stellar cores. Stars where annihilation
contributes substantially to the total energy budget look very different to
those with which we are familiar. Here I explain the general features of stars
modified by dark matter annihilation with the help of a series of grids of
'dark' stellar evolutionary models, and describe the public code with which
they were computed. I go on to discuss possible impacts of dark stars on the
high-redshift Universe, including the history of reionisation. The preliminary
reionisation calculations reproduced here are based on dedicated models for
dark star atmospheres, and for the stellar populations to which dark stars
would belong.
