Abstract: Precise determinations of |V_cb| from B factories are crucial for testing the unitarity of the CKM matrix and obtaining accurate predictions of decay processes with flavour changing neutral current. Inclusive semileptonic B decays offer one of the main avenues for such extraction of |V_cb|. In this seminar I will present some recent developments in the theoretical prediction of this class of decays, in particular the calculation performed in perturbative QCD of the third order correction to the partial semileptonic width and the relation between the on-shell mass and the so-called kinetic mass determined to the same order of accuracy. I will also discuss the perspectivesfor a novel extraction of inclusive |V_cb| based on the leptonic invariant mass spectrum, recently measured by the Belle collaboration, which allows to reduce the set of non-perturbative inputs necessary in the theoretical prediction.