In this paper, we propose a book dewarping model which flattens a curved book page to its original flat rectangle shape. This model generalizes the model proposed by Cao to handle warped book images taken from different point of views instead of only from top of the book surface. In order to do so, we realize the impact of the angle between the camera lens and the book surface and take it into account in the transform model. Based on the new model, the rectification process includes two steps: 1) on the warped book image, find a region which is original a rectangle on a flat page; 2) map each pixel in warped region to a pixel in its original rectangle region. The experimental results demonstrate the effectiveness of our proposed book dewarping approach.