In this paper we review the notions of gonality and Clifford index of an abstract curve. For a curve embedded in a projective space, we investigate the connection between the Clifford index of the curve and the geometrical properties of its embedding . In particular if C is a curve of degree d in P 3 , and if L is a multisecant of maximum order k , then the pencil of planes through L cuts outIf the gonality of C is equal to d − k we say the gonality of C can be computed by multisecants. We discuss the question whether the gonality of every smooth ACM curve in P 3 can be computed by multisecants, and we show the answer is yes in some special cases.