It does make a difference which paper you use to print your book. Keep in mind that there is not one right paper for your book. Here is some information that will help you decide which paper is best. 24# (pound) paper that has a good brightness and opacity will work for most books. But if your book has over 700 pages, a thinner paper (like 20#) might be preferred so the book isn't so heavy or as thick. Coated papers can add a certain feel to your book especially if there are a lot of color pictures. It can work to mix pages in a book (i.e.: color picture pages on slick, coated paper and the rest of the book on 24# book paper) but you will notice that the shades of white will be slightly different. Most people will never notice the difference, but if you are one that it will bother, then I would suggest that you keep the book on all the same paper.
The weight of the paper can get very confusing because of the way that paper was made over 100 years ago. I’ll try to simplify what you need to know. Paper weights are designated by its “basis weight” and there are five different categories that are used. For book paper, there are two categories that are used most commonly, that is “offset weight” and “bond weight.” 20# bond is the same weight or thickness as 50# offset. 24# bond is the same as 60# offset. So if you talk to one printer and he says that he is going to do your book on 50# and other is going to do it on 24#, don’t be confused into thinking that since 50 is twice as much as 24 that the paper is thicker and better. Now you will know what they are talking about and can make a better decision.
There are two more things that are important for you to know about paper. First, is the brightness of the paper. Most paper is much brighter than it used to be 25 years ago. The brightness is a number between 1 and 100 with 100 being the brightest. Usually, a number above 92 is a good whiteness for books. Second, is the opacity of the paper. Opacity is how much you can see through the paper to what is printed on the other side. Check the opacity of several sheets together, like in a book, rather than holding one sheet up to the light. Almost all papers that would work well for a book will have some show-through. You just want to be sure that it isn’t so much that it is distractive to the reader.
All white bond or offset paper that is made in the U. S. is acid free so you don't need to worry about the pages turning yellow and becoming brittle over time. A few years ago you had to search for acid free paper. Not any more. (That is a relief.)
If this is all too confusing for you, don’t worry. Just look at the paper and if it looks good, it should work fine for you.
Email questions and I’d be happy to help.