  We study the Type IIA limit of the M theory fivebrane configuration
corresponding to N=1 supersymmetric QCD with massless quarks. We identify the
effective gauge coupling constant that fits with
Novikov-Shifman-Veinshtein-Zakharov exact beta function. We find two different
Type IIA limits that correspond to the electric and magnetic descriptions of
SQCD, as observed in the massive case by Schmaltz and Sundrum. The analysis is
extended to the case of symplectic and orthogonal gauge groups. In any of the
cases considered in this paper, the electric and magnetic configurations are
smoothly interpolated via $M$ theory. This is in sharp contrast with the
proposed derivation of N=1 duality within the weakly coupled Type IIA string
theory where a singularity is inevitable unless one turns on a parameter that
takes the theory away from an interesting point.
