The 1:1 reproduction ratio really won't be necessary unless the book is of postage stamp size. What will be important is that you use a flat-field lens. The reasoning for use of a flat-field lens is to minimize the effects of barrel or pin-cushion distortion typically associated with zoom and wide-angle lenses. While flat-field lenses are typically associated with macro or micro lenses, a good fixed focal length lens of normal length that focuses fairly close will often produce very good results also. One trick is to lay a heavy piece of non-reflective glass over the pages. This will help to flatten the pages. Also use of polarized, continuous light works best.