Let's denote the number of books in the special collection at the beginning of the month as \( B \).

During the month, \( 39.99999999999999 \) books were loaned out. Since we're dealing with physical books, we can round this number to \( 40 \) books for practical purposes.

According to the information given, 70 percent of the books that were loaned out are returned by the end of the month. Therefore, the number of books returned is \( 0.70 \times 40 = 28 \) books.

The number of books that were not returned by the end of the month is the remaining 30 percent, which is \( 0.30 \times 40 = 12 \) books.

At the end of the month, there are 63 books in the special collection. This number includes the books that were originally there minus the books that were not returned plus the books that were returned. So, we can write the equation:

\[ B - 12 + 28 = 63 \]

Solving for \( B \):

\[ B + 16 = 63 \]
\[ B = 63 - 16 \]
\[ B = 47 \]

Therefore, there were 47 books in the special collection at the beginning of the month.
월 초에 특별 컬렉션에 있는 책의 수를 \( B \)로 표시해 보겠습니다.

한 달 동안 \( 39.99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999