The brightest gamma-ray bursts (GRBs) would be detectable at very high redshifts and so offer a probe of star-formation and galaxy evolution into the reionization era and even beyond. Localisation of their bright afterglows pinpoints their host galaxies, however faint, and can give not only redshifts but also metallicity estimates, information on the presence of dust and molecules, and HI column densities. Statistical samples of well-observed GRBs at high redshift may therefore reveal the evolution of the global star formation rate, chemical enrichment, far-ultraviolet escape fraction and the faint-end of the galaxy luminosity function; all of which are very difficult to establish via conventional galaxy searches. To date, only a handful of z > 6 GRBs have been identified, but their presence at z > 8 begins to realise their potential as searchlights to illuminate the early Universe.