They say that one should not judge a book by its cover. The sheer volume of different covers that have been designed for Killing Mr. Griffin over the years might perhaps be a testament to the unreliability of that conventional wisdom. Over the decades since it was first published, the story has inspired at least a dozen different covers and it is almost impossible to imagine that eleven of them were not designed specifically to counteract the reaction to one of the originals which features an illustration of four of the most unpleasant teenagers imaginable just below the sinister tagline "The plan was only to scare their English teacher."
The problem with this cover is not so much that it features illustrations of four unpleasant teenagers, but rather that the illustrations are representatives of four unpleasant characters. It is worth noting that of the myriad covers which have arrived in its retirement, very few replicate the idea of putting the teenage characters on the cover and on those that do, the teens illustrated are significantly less repulsive, mostly as a result of being significantly more vaguely conceived. The idea of judging this book by its covers becomes prickly simply as a result of their being so many to choose from, but it is that first cover that is problematic.
For one thing, it is quite clear that more work went into that illustration than went into any of the covers which have come in its wake. Which raises the question of why, if the cover was considered so integral to the marketing that it received such care and attention, has it been replaced with so many different concepts? Because, as it turns out, you can judge a book by its cover. It is very easy to dismiss Killing Mr. Griffin as the story of a group of very unlikable leading characters conspiring to kidnap a teacher in order to put a good scare into him for the most narcissistically idiotic reasons imaginable when the cover leaves no ambiguity about just how repellent those characters are.
On the other hand, slap a far more ambiguous hint at the contents ranging from nothing but the title over a noose to two shadowy figures in silhouette with a large pair of eyes looking forward with no immediately obvious emotion and suddenly it becomes impossible to judge the content of the book by its cover.
The point here is not that the novel is badly written or uninteresting. In fact, it is a prime example of how to tell a story about supremely unlikable characters and still keep the reader interested. While the students conspiring to teach a lesson to a person who does not need to be taught anything, much less by them, are the very definition of odious, that does not equate with them not being interesting.
The history of the book covers for Killing Mr. Griffin teaches a supremely valuable lesson. It is much easier to enjoy reading about loathsome people when you are also doing the casting in your mind. Once a marketing team has devised what those characters look like for you—with the result being that they look as abhorrent as they act—it becomes problematic. All those covers which don't replicate the original are proof enough of that.