Other forms: hardcovers
A hardcover book has stiff, rigid covers on its pages, rather than flexible ones. You might prefer hardcover books at home, but tend to pack paperback copies when you travel, since they weigh less.
Hardcover books are the ones that tend to be published first, with firm, sturdy covers protecting the pages. You can also call this type of book a hardback. Paperbacks, commonly published after the hardcover has been out for several months, are floppy, lighter, and cost less to buy. Most library books have a special cover that's called "library binding," but it tends to be rigid like a hardcover.