Abstract: Soon after the discovery of neutrons, the existence of compact stars made entirely from neutrons was predicted in the early 1930s. It's been more than 40 years since the discovery of the first pulsar which confirmed the existence of neutron stars. Since then, we have been able to detect ~2300 pulsing neutron stars (aka. pulsars). While the behavior of highly magnetized matter at supra-nuclear densities still eludes us, we have come a long way to phenomenologically understand these stars in the context of stellar evolution. High precision radio timing observations not only allow us to put stringent constraints on the masses, ages and evolution of neutron stars; they also open up the door to potentially use pulsars as high precision beacons to map the fabric of space-time. I will review the current constraints on the fundamental properties of neutron stars and touch upon how these exotic objects continue to provide us with clues on fundamental problems in physics and astronomy with unprecedented detail.