Search for Relic Neutrinos and Supernova Bursts

We describe the current situation concerning methods to search for relic neutrinos from the Big Bang and from all past supernovae (SNs). The most promising method for Big Bang neutrinos is by the interaction of ultra-high- energy (UHE) neutrinos. For supernova neutrinos, both Super Kamiokande- and ICARUS-type detectors will be important to study both nubar_{e} and nu_{e} fluxes. We also discuss a dedicated supernova burst observatory (OMNIS) being planned for three sites in the world. We also describe the possible analysis of the supernova type-II (SNII) neutrinos, including flavor mixing, that might be carried out in the future.