  The sources and fluxes of superGZK neutrinos, $E>10^{20}$ eV, are discussed.
The most promising sources are reionization bright phase, topological defects,
superheavy dark matter and mirror matter. The energy of neutrinos can be above
the GUT scale ($\sim 10^{16}$ GeV). The predicted fluxes are observable by
future space detectors EUSO and OWL.
