In my presentation, I review the expected performances of the Athena-WFI survey, with a particular focus on the high redshift Universe and the first SMBH science topic. I put these performances in the broader context of present and future missions and facilities in other wavelengths, from optical/IR large-area surveys to mm/sub-mm and radio observations. The unique capability of Athena-WFIto identify obscured sources up to very high redshift, where they are expected to be the vast majority of the AGN population and derive their intrinsic accretion properties,makes it competitive even with the rich landscape of the late '30s.