  We present an updated next-to-leading order analysis of the B -> X_s gamma
branching ratio and photon spectrum, including consistently the effects of
Fermi motion in the heavy-quark expansion. For the Standard Model, we obtain
B(B -> X_s gamma) = (2.57+-0.26^{+0.31}_{-0.36}) * 10^{-4} for the integral
over the high-energy part of the photon spectrum with E_gamma^{lab} > 2.2 GeV,
where the first error reflects the uncertainty in the input parameters, and the
second one the uncertainty in the calculation of Fermi motion. This prediction
agrees with the CLEO measurement of the same quantity within one standard
deviation. From a reanalysis of the CLEO data, we obtain for the total
branching ratio B(B -> X_s gamma) = (2.62+-0.60_{exp}^{+0.37}^{-0.30{th}}) *
10^{-4} using the measured rate above 2.2 GeV, and
(2.66+-0.56_{exp}^{+0.43}_{-0.48{th}}) * 10^{-4} using a fit to the photon
energy spectrum. Both values are consistent with the Standard Model prediction
of (3.29+-0.33) * 10^{-4}. Our analysis contains an improved discussion of
renormalization scale dependence and QED corrections. We also discuss the
sensitivity of the branching ratio and photon spectrum to hadronic parameters
such as the b-quark mass, and to possible contributions from New Physics beyond
the Standard Model.
