Assume that the observer is in the reference frame outside the Earth, and finds that Earth simultaneously rotates about its axis of rotation and revolves around the Sun. As seen from North Pole, the Earth rotates in the counter-clockwise direction. According to the observer, the book on a table on Earth will move faster in night and slower in day.
The book on the table has two velocity vectors, one due to the rotation of Earth and the other due to its revolution around the Sun. During the night, both these velocity vectors point in the same direction and add to account for increased speed of the book.
However during the daytime, the velocity vector due to the rotation of Earth changes its direction such that both the velocity vectors are 180° out of phase. This reduces the net velocity of book together with its observed speed.