This book illustrates observed values and properties of neutron stars, field theoretical approaches of hadrons to high density matter, such as nuclear and hyperonic matter, signals of dynamical phenomena, hadronic and hadron-quark neutron stars, radiations from high density matter and supernova phenomena. However, it is not intended to report facts and results at front-line research fields, because numerous conference reports suffice the objectives. The purpose of editing the book is to review related areas of nuclear physics and astrophysics in terms of equations of state of high density matter so as to promote mutual understandings and their consistent progresses. It is focused on theoretical relations between equations of state (EOS) and observables. These topics of high density matter, which extend across many fields of physics, should be frequently reviewed for researchers and people in general.