The paper by James M. Lattimer and Madappa Prakash explores how current and proposed observations of neutron stars can help understand their interiors and key unknowns, such as typical neutron star radius and maximum mass. The authors consider observations from various sources, including photons (from radio waves to X-rays), neutrinos, and gravitational waves. They detail how precise determinations of structural properties can significantly restrict the poorly understood equation of state (EOS) near and beyond the equilibrium density of nuclear matter. The paper begins with a theoretical analysis of neutron star structure, including general relativistic limits on mass, compactness, and spin rates. It reviews recent observations such as pulsar timing, optical and X-ray observations of cooling neutron stars, and X-ray observations of accreting and bursting sources. The authors discuss neutrino emission from proto-neutron stars and how neutrino observations from supernovae might impact our knowledge of neutron star interiors, mass, and radii. They also explore the effects of superstrong magnetic fields on the EOS and neutron star structure, and the potential differences in gravitational wave emissions between normal neutron stars and self-bound strange quark matter stars. The paper further examines laboratory measurements that can restrict the range of nuclear parameters, such as the incompressibility, symmetry energy, and nucleonic effective masses. It concludes with an outlook on the future of neutron star observations and the potential for new insights into the nature of dense matter.The paper by James M. Lattimer and Madappa Prakash explores how current and proposed observations of neutron stars can help understand their interiors and key unknowns, such as typical neutron star radius and maximum mass. The authors consider observations from various sources, including photons (from radio waves to X-rays), neutrinos, and gravitational waves. They detail how precise determinations of structural properties can significantly restrict the poorly understood equation of state (EOS) near and beyond the equilibrium density of nuclear matter. The paper begins with a theoretical analysis of neutron star structure, including general relativistic limits on mass, compactness, and spin rates. It reviews recent observations such as pulsar timing, optical and X-ray observations of cooling neutron stars, and X-ray observations of accreting and bursting sources. The authors discuss neutrino emission from proto-neutron stars and how neutrino observations from supernovae might impact our knowledge of neutron star interiors, mass, and radii. They also explore the effects of superstrong magnetic fields on the EOS and neutron star structure, and the potential differences in gravitational wave emissions between normal neutron stars and self-bound strange quark matter stars. The paper further examines laboratory measurements that can restrict the range of nuclear parameters, such as the incompressibility, symmetry energy, and nucleonic effective masses. It concludes with an outlook on the future of neutron star observations and the potential for new insights into the nature of dense matter.