On my kindle paperwhite you can open the book then touch the top of the screen. Three dots appear at the top right. When you press them a menu appears - one if the options is About This Book. That's the blurb about the story etc. Is that what you meant?
I think I get what you mean. I buy tons and then I have no idea from the title whether it's a gritty murder mystery or a London gal rom com (okay I can probably guess from the title sone times). Shirt if putting them straight into genre folders when buying I generally have to just start it and see whether someone gets killed or moans about a date.