The 1929-1930-1931 paradox is described in simple terms by Arthur Ransome scholar Bill Wright: In Swallows and Amazons (SA), the treaty of offence and defence signed by the Swallows and the Amazons is dated "August 1929." There are many instances in Swallowdale (SD) that refer to action from SA as happening the previous year, but the card left on the summit of Kanchenjunga is dated "11 August 1931." Which year, therefore, is correct for SA--1929 or 1930?