Reionization and Cosmology with 21-cm Fluctuations

Measurement of the spatial distribution of neutral hydrogen via the red-shifted 21-cm line promises to revolutionize our knowledge of the epoch of reionization and the first galaxies, and may provide a powerful new tool for observational cosmology from redshifts 1 < z < 4. In this review we discuss recent advances in our theoretical understanding of the epoch of reionization (EoR), the application of 21-cm tomography to cosmology and measurements of the dark energy equation of state after reionization, and the instrumentation and observational techniques shared by 21-cm EoR and postreionization cosmology machines. We place particular emphasis on the expected signal and observational capabilities of first generation 21-cm fluctuation instruments.