hardback
A book with stiff, durable covers made from hard cardboard.
A hardback is a book with stiff, durable covers made from thick cardboard wrapped in cloth or paper. If you run your hand along your bookshelf, you can easily tell the difference: hardbacks feel solid and substantial, while paperbacks bend easily in your hands.
Publishers typically release important books as hardbacks first. New novels by popular authors, reference books, and special editions usually come out in hardback because the sturdy binding protects the pages and helps books last for decades. Libraries prefer hardbacks because they survive being checked out repeatedly by many readers.
Hardbacks cost more than paperbacks because they use better materials and require more complicated manufacturing. A hardback novel might cost $28, while the same book in paperback costs $16. Collectors and people who love books often prefer hardbacks for their favorite titles because they look impressive on shelves and stay in good condition longer.
The word hardcover means exactly the same thing. You might also hear people say a book is in “cloth” if it has a fabric covering, though most modern hardbacks use paper printed to look like cloth. When a book is released “in hardback,” it means that's the only version available, usually for several months before a cheaper paperback version appears.