Most books, when they are first published, do not have forewords. They might have author’s notes, afterwords, or similar additions to the main text, but these are usually located after the story, and they tend to focus on the background and thought involved in the writing of the story, not the reading of it. As a given book gains attention, though, and especially if it reaches a certain level of fame, it tends to acquire more front content: forewords, prefaces, introductions, and other contextualizing materials. In some cases, especially for translations of historical works or for certain types of nonfiction pieces, these can be quite helpful for orienting the reader ahead of the text, but those cases are the exception. Most of the time, and especially for fiction, such materials would be more appropriately read after the main text, if you should read them at all.
The problem isn’t spoilers, per se. Most works with forewords or similar materials have been elevated to at least a minimal level of the “classics” pantheon, and most readers will therefore be at least vaguely familiar with the basic plot and contents of the book well before reading it, unless they were fortunate enough to encounter the classic before encountering its ripples. I went through a classics phase (mostly classic science fiction, like Jules Verne and HG Wells) in about the fifth grade and consider myself fortunate because I read many of these books before I encountered their aftereffects and interpretations in the broader culture. It is an experience I cannot replicate for most classics I read these days, which is unfortunate for a lesser version of the same reason I find forewords so damaging: it becomes impossible to read the book as it is without bringing preconceived notions into it.
Books are not solely stories the author tells the reader. It took me a long time to come to terms with this notion from a writing perspective, for all I’ve long accepted it and even advocated it from a reading perspective. Despite the seemingly static nature of the written word, books are a conversation between author and reader, and every reader will take something different from a text. That is part of the unique experience of reading, it is part of what makes reading so valuable, and it is why managing reader expectations is such a vital part of effective publishing. Going into a story expecting something very different from the story which is written is a sure recipe for disappointment. Genre, cover art, book reviews, and recommendations all influence our expectations going into a new book, or even one we’re rereading. Forewords take this a step further by dictating, not just influencing, the expectations we should have going into a text.
The specific contents of forewords are not the problem. Not all readers will necessarily agree with them, they vary widely in quality and insight, and many readers don’t bother with such extra material when they read (that used to be me before I first started reading such materials to gain insight into the publishing industry, and then because they are often quite helpful in historical works and translations). However, by presenting these materials first, before the reader engages with the story on the story’s own terms, and not those provided by the foreword, the reader’s entire experience with and expectations of the story are distorted. The foreword to the copy of LeGuin’s The Dispossessed which I recently read is guilty of this, trying to dictate the message readers are “supposed” to get from the book and dwelling on the ostensible impact of the social context in which the book was written.
Again, I wouldn’t think of this as being such a problem if the material were presented after the main text. It’s the same reason I try to minimize reading book reviews prior to reading a book, or even before I’ve written my own review, lest I bias my perception of the book and what I might want to say about it (of course, I sometimes pay for this by reading books which the reviews would have led me to avoid, and I do realize the irony this creates for an author of weekly book reviews). I doubt that we can change the publishing industry, which has numerous incentives to keep forewords where they are, but consider this a call to action, or a reminder, that forewords are usually best read afterwards.
