ebooks | Reading Nook Books on non-Nook tablets (Reply)

I was looking to purchase a book from Barnes & Noble except it only comes in hardcover and Nook Book. I don't want to purchase a hardcover but I've never purchased a Nook Book before. I have a tablet (Sony Xperia) and I'd like to read this book from it instead of at my computer. Would I be able to purchase it from my computer and transfer it to my tablet or would I need to purchase it directly from my tablet? Also, will I be able to read a Nook Book from my non-Nook tablet and how so? Thank you in advance!