A number of studies have shown that second or foreign language learners can acquire vocabulary through reading. The aim of the study was to investigate (a) the effects of reading an authentic novel on the acquisition of 3 aspects of word knowledge: spelling, meaning, and collocation; (b) the influence of reading on the acquisition of partial and deeper knowledge of the words; and (c) the relationship between word frequency and learning gains. The results show that there was significant improvement in all three aspects of word knowledge. The measuring instrument detected greater partial than deeper knowledge gains in word meanings and collocations. The greatest learning gains in all three aspects of word knowledge were demonstrated for the words that occurred between 11 and 20 times in the text. The findings suggest that incorporation of extensive reading into language learning programs can contribute to significant improvement of learners' vocabulary knowledge.