Those Helpful Introductions

When reading a classic that has a "helpful" introduction, I generally skip it and go straight to the story. In my experience the introduction usually discusses details of the book that make no sense unless I've already read to the end. I picked up The Virginian the other day and after reading the bio piece on Wister and a spiffy life timeline, I glanced at the beginning of the introduction. It looked like it might be useful. And it was. It goes on for pages talking about the western genre and The Virginian's place in it's development. Turns out it is the prototype for what we think of as a western today. I read along happily until about 3/4 of the way through when all of a sudden Mr. John G. Cawelti, author of the introduction, gives away the ending! It sounds like it's going to be a good ending, but golly, did he have to give it away? The intro was going so well until then. I should have known better. I should have known that introductions to classics always give the ending away. But I was fooled. What is it about these intros anyway? Why do the scholars that write them assume the reader either already knows how the book ends or doesn't care being told about it if she doesn't know? Why does the scholar write the introduction with the assumption that the reader has already read the book? To me a discussion of the details of the book is not an introduction and should be placed at the end of the book as an afterward or something. If I were ever asked to write an intro to something, I'd write a real introduction. I'd assume the person had not read the book yet. I'd place the work in historical context, talk about the writing of the book, it's reception by the public. I'd write about the major themes in a general way, as a signpost for the reader to look out for. I would not give away the ending. I wouldn't want to ruin the wonderful suspense of it. It is not fair to assume the reader knows the ending because the book was written a long time ago. It's not fair to assume that if the reader doesn't know the ending it's okay to ruin it. I know no reader who wants the ending to be given away before he gets to it. Bah. I'll stop my grumbling now. If you are planning on reading The Virginian and you have the Barnes and Noble Classics edition, you are forewarned--don't read the introduction!