Taking part in only the weak interaction, the neutrino is a unique messenger in the astrophysical context - for example, it can probe regions inaccessible by more conventional means such as photons. A prime example of this is the study of the inner workings of supernova explosions. However, we currently only have one supernova detected in neutrinos. In this talk, I will first review supernovae and motivations for their study. In the second half I will address the prospects for detecting the cumulative neutrino emission from all past supernovae (the so-called diffuse supernova neutrino background), where I will demonstrate the imminent detection at Super-Kamiokande. I will also further discuss more rare but significant non-thermal neutrinos from nearby supernovae, motivated by the established supernova-GRB connection. Interesting physics can be learnt from neutrino detections.