Luminous, high redshift (z>6) quasars are formidable probes of the universe in the Epoch of Reionization. They are observed to already host supermassive (>108 Msun) black holes in their centers, and to reside in the earliest, most massive galaxies, where they are thought to be surrounded by large galactic overdensities.
In this talk, I will present an overview on our effort to discover these new remarkable sources using large-area optical/NIR sky surveys, and to characterize the properties of their innermost regions, such as their black holes and broad line regions. I will also show our investigation of the environments of few quasars at high-z, reporting in particular deep, multi-wavelength follow-up observations of ALMA-detected companion galaxies close to quasars.
Finally, I will present a newly discovered z~6.8 radio-loud quasar, his peculiar radio properties, and depict our initial investigation on how the radio-loud/radio-quiet quasars samples compare at z~6.