THE nature of the sonic boom problem is briefly reviewed, and the experimental evidence relating to the Whitham‐Walkden theory presented. Although many atmospheric effects cannot be fully accounted for, the theory is used to predict ground overpressures directly beneath the proposed Concorde flight track. Using the work of Rao, over‐pressure values up to 2·0 lbf/ft2 are predicted for the initial climb and acceleration, as opposed to 1·6–1·3 lbf/ft2 for the cruise. Structural damage is thus unlikely, but until people are accustomed to the booms, they will cause annoyance, especially in the region 130 to 320 miles from take‐off. The minimum sonic boom for an aircraft of given length, volume and total lift is also discussed. Since the Concorde configuration is fairly close to the optimum, it seems that any significant reduction in sonic boom will mean an increase in the supersonic flight altitude or a decrease in aircraft weight.