A notable area of methodological contribution from Paul Nation is his research and theory surrounding extensive reading and vocabulary acquisition. Through his 1997 literature review, Nation has determined that in order for extensive reading to be valuable, the proper level of book must be selected for the learner. This creates opportunities for the learner to read many books at their level. He mentions that a book which is deemed the "right fit" for a learner, requires the majority of vocabulary to be already familiar to the reader with a maximum of two unfamiliar words for every 100 words read. Nation suggests that in order for the new vocabulary to remain present and understood in the learners mind, the quality of the meetings with new words must be memorable. Nation then outlines 4 levels of quality meetings with words.
