Extensive reading for second language learners have been widely documented over the past few decades. However, few studies, if any, have used a corpus analysis approach to analyze the vocabulary coverage within a single-author story series, its repetition of vocabulary, and the incidental and intentional vocabulary learning opportunities therein. The current study analyzes 48 publications in the Magic Tree House series and compares (1) the vocabulary coverage across the series with the three word lists developed for middle school and high school in Taiwan; (2) the word-type repetition patterns observed in the corpus across the three word lists; and (3) the prospects of incidental vocabulary learning, word list learning, and intensive new word learning during extensive reading of the series. The rich Magic Tree House corpus makes repeated use of vocabulary from all three word lists, and the findings indicate that extensive reading can support word list learning, especially of the Middle School Basic 1,200 list. Research finding indicates that acquiring words from word lists prior to reading is not as effective as focusing on new word types as they appear in the series; as the number of readings increases, so too do the opportunities for incidental vocabulary acquisition.