The production of written syntheses, which requires reading various sources and integrating information from these sources into one's own text, has been characterised as a potentially useful task for promoting constructive learning. This article describes research aimed at examining and characterising written syntheses and the processes involved in producing them. A case study was carried out of 45 students from four different educational levels (ranging from secondary school to university) performing synthesis tasks set by their teachers. An analysis was made of the synthesis tasks set and the syntheses produced, the prototypical procedures carried out at each educational level, and the quality of the written products. The results corroborate the view that producing syntheses is difficult even for university students with a high degree of reading and writing competence. They also show that the difficulty level of the texts and tasks set by the teachers is generally high and that this difficulty increases as students go up the educational ladder. It was found that the younger students adopted more sequential procedures, whereas more experienced students employed more recursive approaches. It was concluded that there is a need to teach students the epistemic uses of reading and writing. (Contains 5 figures, 2 tables and 2 notes.)