Select the page size of your book. Format 8.27" x 11.7" US Letter 5.83" x 8.27" 6" x 9" 21cm x 21cm * Fill in the number of pages of your book. Number of pages Enter the royalties percentage on the sale of your book. The lower this percentage, the lower the cost of your book on the UniBook website. Your royalties percentage(0-200%)