
Max M. answered 01/22/19
Harvard Literature major with 20 years of coaching writers
Assuming you're reading in English, there shouldn't be many versions of Frankenstein around--multiple publishers, sure, but the texts should all be the same. The only reason to worry about which edition / publisher to get is that it makes it easier to discuss in class if everyone has the same page numbers.
That said, if you're looking at an ABRIDGED edition, don't get that unless the teacher explicitly says--that will have stuff cut out of it.
Definitely avoid a CHILDREN'S version, unless, you know, you are a child.
Also, this won't apply to Frankenstein, but different versions matter A LOT if you're reading something in translation. First of all, check whether the professor has assigned a specific translation. If not, you can look at online reviews, or, better yet, if you can find someone at a bookstore who's read it, ask them what they recommend. If all that fails, my general rule of thumb is that with translations, the newer the better. It's not a perfect formula, but translations age much less well than the works themselves, so if you get Constance Garnett's translation of Dostoyevsky, which is over 100 years old (and still often assigned, unfortunately), you'll probably find the book slow, stodgy, and dull, but if you get, say, the Peavar and Volokhonsky translations, mostly done in the last 15 years, you'll probably like the book a lot more.
But again, that's a guideline for the future--Frankenstein's in English, so you don't have to worry about that for this one.