"Hardcover" refers to a type of book or journal that has a rigid or firm cover made of thick and sturdy material, like cardboard. It is more durable and long-lasting compared to books with flexible covers, such as paperbacks. Full definition
Until quite recently it was a solid, slow moving «book - discipline,» an academic discipline in which most of the important material was published in hardcover books. (religion-online.org)
You might commonly see this book binding style in paperback novels however it is also used in hardcover books. (edwardsbrothersmalloy.com)
That said, not every printed book is available in e-book form and the e-book release is sometimes delayed somewhat, to maximize sales of hardcover editions. (consumerreports.org)