In this project, 54 Iranian pre-intermediate EFL learners (16 to 21 years) participated in 15 sessions in which they were asked to read and study books from a structured series of L2 reading materials. Half the students studied with relatively easy materials ('i - 1'), that is, materials rated as being below their competency level. The others studied with reading materials rated at slightly above their competency level at the outset ('i + 1'). Using a before and after design, students were retested after 15 weeks. On a test of L2 reading comprehension, means testing revealed both groups showed marked increases, but the 'i + 1' group was higher than the other group (effect size 1.1). On an assessment of reading motivation, the 'i + 1' group increased significantly, whereas the other group showed no change (effect size 1.58). We suggest that, under supporting conditions, there can be clear benefits for EFL learners to spend time mastering L2 materials above their level of competency.