A description of ignition and combustion of boron particles is developed with the aim of obtaining a theory that is as simple as possible yet consistent with available data. For the ignition stage the model involves equilibrium reactive dissolution of B in the thin B2O3(ℓ) layer to form dissolved BO, for example, surface attack of BO by O2(g) and by H2O(g) to form BO2(g), and HOBO(g), respectively, vaporization of B2O3, and later clean-surface attack of B by O2(g) to form B2O2(g). For the combustion stage the mode involves only the last of these processes. Values of relevant rate constants are identified that achieve agreement with experiments. Early laser-ignition experiments, not previously explained quantitatively, are employed for obtaining needed dry-gas rate parameters. New experiments on ignition and combustion of boron suspensions in hot combustion products of a flat-flame burner are performed to test adopted values of wet-gas rate parameters. Results provide a basis for calculation of ignition and combustion of boron in propulsions applications.