The theme of erotic bookplates has not been chosen pruriently, or without due consideration. Ex-libris are the result of a commission or at least of a contact between an artist and a person wishing to have a bookplate. It is essentially a private object, which a person pastes into his books, or which he exchanges with fellow collectors if he wishes to do so. Thus the subject of the bookplate is decided by the artist and the owner together; when it is an erotic subject, usually it is because the owner has in his library a small ‘inferno’ of erotic books, which he wishes to mark with a bookplate. As to collectors who commission erotic ex-libris for exchange, their motives are more nebulous. Perhaps the most justified reason lies in the nature of erotic art: it does not leave the observer indifferent, and perhaps more than any other art subject, it does not tolerate mediocrity. Unfortunately, today, one sees many mediocre ex-eroticis, which are no more than smutty pictures and not worthy of being collected. But there have been since the end of the last century, a number of such bookplates which are by talented artists and an honour to the genre.