We study the inclusive production of Λ (Λ̄) in several high energy collision processes (e+e−, e±p, ν(ν̄)p, pp), in view of an accurate determination of the unpolarized and polarized fragmentation functions of a quark into a Λ (Λ̄). For polarized fragmentation functions the inaccuracy and the scarcity of present data do not allow to distinguish between various theoretical models. We will indicate h...