The horizon of expection(s) (German: Erwartungshorizont) goes beyond a single reader's expectations. According to Hans Robert Jauss, the evaluation of a literary work requires a reconstruction of the "horizon of expectation(s)" that the author's contemporaries would have brought to that work. This "horizon of expectations" refers to the set of expectations and assumptions witch which readers from a specific generation and a specific culture read literary works. (Readers are not necessarily constantly aware of the entire set of expectations while reading.) Obviously, Shakespeare's contemporaries would have approached Hamlet with totally different expectations than early 21st-century readers or theatre goers. For example, theatre was not as highly regarded as a genre as today, and Elizabethans would have been much more familiar with the conventions of revenge tragedy.
For Jauss, each of a work's "receptions" by successive generations of readers is a valid object of study; he described this succession of receptions as a “continuous establishing and altering of horizons”. A specific literary work may expand one's (aesthetic) horizon (in which case it is valuable) or not (e.g. formula fiction).