Vus from Kℓ3 Decays

Important progress made this year, both in theory and in experiment, helped solving the problem of 2σ–deviation from the unitarity of the first row elements in the CKM matrix. Today we have, |V us | 2 + |V ud | 2 + |V ub | 2 − 1 = −0.0008(13), −0.0010(13), or −0.0005(13), depending on whether the q 2-dependence of the relevant K ℓ3 form factor is considered as pole-like, linear or quadratic function, and on the Leutwyler-Roos value of f + (0) = 0.961(8), whose validity has recently been reinforced by lattice studies. In this talk we summarize the recent developments.