2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/127178We review the X-ray studies of the highest redshift quasars, focusing on the results obtained with Chandra and XMM-Newton. Overall, the X-ray and broad-band properties of z>4 quasars and local quasars are similar, suggesting that the small-scale X-ray emission regions of AGN are insensitive to the significant changes occurring at z=0-6.2 pages, to appear in "The Central Engine of Active Galactic Nuclei" (Xi'an, China, October 2006). Eds. Ho L.C. & Wang J.-M., ASP conference seriesAstrophysicstext