This is the 202nd most frequent Hungarian word.
nemcsak
"Not only"
Here, 'nemcsak' is used to introduce the first part of a compound statement, emphasizing the addition of the second quality.
Nemcsak esős az idő, hanem hideg is.
Not only is the weather rainy, but it's also cold.
In this sentence, 'nemcsak' establishes a connection between two groups of participants, providing an inclusive listing.
Az ünnepségen nemcsak diákok vettek részt, hanem tanárok is.
At the celebration, not only students but also teachers participated.
Here, 'nemcsak' serves to link two groups to which the statement about the book's interest applies.