Stanley Unwin, The Truth About Publishing (London: George Allen & Unwin Ltd., 1929), pp. 320-322:
The publication of translations is highly speculative, much more so than the publication of an original work, because there are in effect two authors to pay instead of one, and both, as a rule, call for immediate payment and are unable or unwilling to let their remuneration depend upon the result. Foreign authors and publishers who have heard of the wonderful sales of some particular translated book are apt to have the most fantastic ideas of the value of the English translation rights, and if the word “America” is breathed, I have known foreign publishers name a figure for which one would think they would be pleased to sell their whole business. Even twenty years ago, translation rights were almost invariably sold for a small lump sum; to-day the most impossible royalties are asked. Probably the fairest plan to both parties is a lump sum for a definite number of copies with a royalty thereafter. It would seem to be clear that if a royalty is granted from the start, it should only be a proportion of what would be paid for an original work. In other words, there is no justification for paying a foreign author plus a translator more than would be paid for a corresponding work by an English author. This sounds obvious, but one constantly encounters publishers (American publishers in particular) who in the same breath admit that they cannot afford more than 10 per cent, royalty for a work by an unknown writer, and that they have just agreed to pay 10 per cent, for some translation rights of a work by an author of whom few people have ever heard. They seem oblivious of the fact that by the time they have paid the translator they are probably paying the equivalent of 20 per cent, for authorship. One such publisher recently admitted to me that he had never yet made any money on translations. I am afraid he never will.