Reading is a highly complex activity that can be described according to different interacting processing levels. These levels correspond to the use of specific kinds of knowledge. This paper presents a survey of reseach data on reading, with the focus on reading a foreign language, especially when related to previously acquired languages. Most of the data on the reading process come from cognitive psychology and deal with reading L1 English. Data and hypotheses on word recognition and sentence processing both in other languages and in foreign language reading are considered where possible.