Because Robin: Lady of Legend is not currently available as a print book (it is an ebook available exclusively from Amazon.com), it doesn’t have an exact page count. However, its approximate page count is 400 pages (slightly less than Harry Potter and the Prisoner of Azkaban), based on the number of words in both books. Hope that helps!
Update: Amazon has listed its estimate of Robin’s book length as 277 pages, based on a standard 6″ x 9″ paperback book with 11 point font size. I can tell you that the printed version would definitely be longer than 277 pages, but you can use that number if you want, since that’s what Amazon shows.