A definition of “biblioklept,” from William S. Walsh’s strange and wonderful 1909 ‘cyclopedia, Handy-book of Literary Curiosities:
Biblioklept, a modern euphemism which softens the ugly word book-thief by shrouding it in the mystery of the Greek language. So the French say, not voleur, but chipeiir de livres. The true bibliomaniac cannot help feeling a tenderness for his pet fad, even when carried to regrettable excesses. Perhaps he has often felt his own fingers tingle in view of a rare de Grolier, a unique Elzevir, he knows the strength of the temptation, he estimates rightly his own weakness; perhaps, if he carries self-analysis to the unflattering point which it rarely reaches, save in the sincerest and finest spirits, he recognizes that his power of resistance is supplied not by virtue, but by fear,—fear of ilie police and of Mrs. Grundy. In his inner soul he admires the daring which risks all for the sake of a great passion. When a famous book-collector was exhibiting his treasures to the Duke of Sussex, Queen Victoria’s uncle, he apologized to his royal highness for having to unlock each case. ‘• Oh, quite right, quite right,” was the reassuring reply: “to tell the truth, I’m a terrible thief.” There are not many of us who are so honest. Nevertheless, the epidemic form which bibliokleptomania has assumed is recognized in the motto which school-boys affix to their books, warning honest friends not to steal them. ” Honest may, of course, be a fine bit of sarcasm. But one prefers to look upon it as indicating a subtle juvenile prescience that the most honest and the most friendly will steal books, as the most honest will cheat their dearest friends in a matter of horseflesh.