Abstract: Heavy Quark Expansion, an approach allowing to treat the strong dynamics in the heavy flavor decays directly on the QCD basis, has recently undergone the critical comparison with the new precision data coming, in particular, from the B factories. An impressive agreement was found in quite different inclusive decays. I also address a few recent developments in theory, among them a `BPS' expansion for B and D mesons. The so-called `1/2 > 3/2' puzzle for the B decays into excited charm states, finally, is being resolved in favor of the theory, and some other dynamic predictions are confirmed by the new data.