"A translation is like health: if it's good, you don't notice it. But if it's not (or if some reviewer thinks it is not), it becomes very important and can ruin a whole book, just as even a minor health problem can ruin your whole life. Every translator knows that the people who review books usually say nothing at all about the translation; you can be very pleased if you read: "The author has been well served by his/her translator" or "... in the felicitous translation of ..." But woe to the translator if anything is wrong: in that case the flaws of the translation can easily take up a whole paragraph or more."