  We present a theory describing the superconducting (SC) interaction of Dirac
electrons in a quasi-two-dimensional system consisting of a stack of N planes.
The occurrence of a SC phase is investigated both at T = 0 and T 5 0. At T = 0,
we find a quantum phase transition connecting the normal and SC phases. Our
theory qualitatively reproduces the SC phase transition occurring in the
underdoped regime of the high-Tc cuprates. This fact points to the possible
relevance of Dirac electrons in the mechanism of high-Tc superconductivity.
