You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
To_Kill_a_Mockingbird

Context:
Despite her editors' warnings that the book might not sell well, it quickly became a sensation, bringing acclaim to Lee in literary circles, in her hometown of Monroeville, and throughout Alabama. The book went through numerous subsequent printings and became widely available through its inclusion in the Book of the Month Club and editions released by Reader's Digest Condensed Books.

Question:
The book's availablity increased through inclusion in what book service?

Book of the Month Club