How do I download books?

Book Crawler is not an ebook reader, but instead is intended to catalog your books in a central location.  It is possible to download books available via Google Books and iBooks.  To do this via Google Books (from the home screen), press Books -> New -> Google Books.  You can use the filter to select the type of book you are interested in (e.g. free or paid eBook).  After entering the isbn, title, and/or author you are interested in, press a book you would like.  Now press the "i" button -> "Edition Information".  You should see a row that says Google Preview and a row that has a link to downloading the book via Google Books.  Pressing the last button will redirect you to Safari to continue your purchase through your Google account.  If it is a free book, the last row will contain a link to the pdf and/or epub version.  Selecting one of those will redirect you to Safari where you can continue download of that book.  To download a book via iBooks, press the search button then Apple Store.  After selecting a book, you will be redirected to iBooks.