The epistolary structure is quite flexible: nineteen correspondents in all, with at least twenty-two different recipients. Usbek and Rica by far dominate with sixty-six letters for the former and forty-seven for the latter (of the original 150). Ibben, who functions more as addressee than correspondent, writes only two letters but receives forty-two. Likewise, an unnamed person (designated only as ***) – if always the same – receives eighteen letters and writes none at all. There is even one complete anomaly, a letter from Hagi Ibbi to Ben Josué (Letter 37 ), neither of whom is mentioned elsewhere in the novel.