Transferred intent

I was just skimming through Umberto Eco's Serendipities: Language and Lunacy at Shakespeare & Co. The book looked like a great compendium of anecdotes to read through, especially the one mentioned on the back cover which talks about Leibniz and the I Ching. As I was putting it down, I noticed that it was translated by Umberto Eco. Translation is notoriously tricky, both as a concept and in practice, so I'm not sure there is a good answer to this question, but I'm wondering what it means to translate one's own book.

It seems to me that what's actually happened is that there are two versions of the book, an English one and an Italian one, rather than one being a translation of the other. Of course, one of the two is chronologically prior. But is that all it takes for one to be a translation of the other? I don't think the distinction between Italian original/ English and Italian version/ English version is a distinction without a difference. The difference is that in the things which I want to call proper translations, the translator is limited to the source text in order to determine how the original author would have expressed his or herself in the new language. But when an author is writing their own work in a second language, there is no such constraint. They have direct access to their intentions, rather than being limited to a secondary source.

I'm pretty sure Nabokov has written an essay on this topic, but I can't remember what he said. Any thoughts from readers are also much appreciated.

Update: Either haloscan is screwed up, or my computer is, or both. At least for me, this post shows up with Comment (0) under it. In fact, there is a thoughtful comment which I recommend reading if you found this post interesting.