It is amazing what a translator can do -- or cannot do. Normally when they get to translate a book, it is already published, having gone through many rounds of editing and proofreading until the author is absolutely satisfied with its content and format.
But a book can sometimes contain errors overlooked by the most experienced authors, editors and proofreaders. If it is a book that is traditionally published, then there is nothing a translator can do, apart from notifying the publisher and hoping (sometimes desperately) that these errors will be corrected in the next edition, be it the paper-based or electronic version. If there is no more edition forthcoming, then the errors will have forever stained the book.
On the other hand, if there are errors in a self-published ebook, then the translator can easily notify the author about them. The author can then quickly update the ebook and re-issue it -- and viola! The ebook is now one step closer to perfection, and its readers will never know the errors ever existed.
In either case, because a translator has to “crawl” through every single word in a book in the translation process, they are the perfect person to check for errors. Sometimes it can be a misspelled name, a wrong moment of the day, or a different location from where a character or an event should be. The translator understands these errors can be overlooked, particularly in the later pages of the book when everyone reading it becomes a bit dizzy and cross-eyed. They will just quietly correct the errors in the translation and return everything to normal.
A translator can also serve as editor, even though it is not and should never be their job to change anything in a book. The translator can only follows the story’s development and dutifully translate every word, while lamenting how sluggishly this scene is written, how terribly unnatural that character is shaped, or how the author keeps repeating everything like a naïve puppy chasing its tail. The translator sees -- and often feels -- that something in the book is not quite right, but there is nothing they can do! That sense of helplessness (and hopelessness) can often drive them crazy!
The translation of a book is as much the translator’s baby as the book is to its author. The translator aspires to give life to their translation, as much as an author can do magic and make a book “shine”. For this reason, a translator always tries to do the best to a book, even by conducting an often-too-late-to-be-useful edit or proofread. Hopefully, in every language, a book and its author can be presented at their best.