Keith Thomas in the London Times:
Look at these people! They suck each other! They eat each other’s saliva and dirt! — Tsonga people of southern Africa on the European practice of kissing, 1927
In what must still be the longest single work devoted to the kiss — Opus Polyhistoricum . . . de Osculis — the German polymath Martin von Kempe (1642-83) assembled 1,040 closely packed pages of excerpts from classical, biblical, legal, medical and other learned sources to form a sort of encyclopaedia of kissing. He listed more than 20 types of kiss. These included the kiss of veneration, the kiss of peace, the kisses bestowed by Christians on images and relics, and by pagans on idols, the kissing of the Pope’s foot, the kiss bestowed by superiors on inferiors, the kiss used in academic degree ceremonies, the lovers’ kiss, the lustful and adulterous kiss, the kiss exchanged by couples sealing their marriage vows, the kiss of reconciliation, the kiss carrying contagion, the hypocritical kiss and the kiss of Judas.
More here.