Integral methods in astronomical spectroscopy

We discuss the milestones of development of the integral methods used in the optical spectroscopy of astronomical objects. We analyze the reasons why some of these methods did not get wide practical application. We demonstrate that a combination of integral methods with multichannel detectors allow increasing the efficiency of the existing astronomical telescopes while pursuing the given spectroscopic programs. A technique of radial velocity measurements not susceptible to positional errors, typical of diffraction spectroscopy, is as well discussed.