  This article gives a very brief introduction about measuring the mass and
radius of neutron star from X-ray observations. The masses and radii of neutron
stars can be determined from photospheric radius expansion bursts in low-mass
X-ray binaries, X-ray pulse profile modeling in accreting X-ray pulsars,
gravitational redshift measurement in low-mass X-ray binaries and thermal X-ray
spectral fitting in quiescent low-mass X-ray binaries.
