There are 7 books which are arranged in 7 places.
So the total number of ways is:
[tex]\begin{gathered} _7P_7=\frac{7!}{(7-7)!}=7! \\ =7\times6\times5\times4\times3\times2\times1 \\ =5040 \end{gathered}[/tex]
Hence there are 5040 ways to arrange the books.
