Abstract: In this paper we clearifv the relation between Pauli, undotted and dotted two components and Dirac spinors, as defined by physicists, and Spinors - elements of certain minimal left (or right) ideals in appropriated Clifford algebras IR p,q. Our approach is based on the notion of the Spinorial-metric in Spinor-space and the fact that Spin + (p,q) is the invariant group of thc Spinorial-metric for p+q < 5. Particularly important results are the representations in Ir 1,3 (the space-time algebra) of the undotted and dotted two component spinors and Dirac spinors Ver menos