Why do old paperback books feel warmer in your hands than hardcovers?

The sensation of 'warmth' when holding an old paperback compared to a hardcover is all about how quickly heat transfers out of your hand into the book. When you touch something, it feels warm or cold depending on how efficiently it draws heat from your skin.

Old paperbacks are often made with rougher, less dense paper that contains many tiny air pockets. Air is a poor conductor of heat, so these air pockets in the porous paper act as insulation. This slows down the rate at which heat leaves your hand, making the book feel warmer.

Hardcovers, by contrast, use denser, smoother paper and rigid covers made from thick cardboard or board, often wrapped with coated material. These dense materials lack insulating air pockets and are better at conducting heat away from your hand. As a result, hardcovers wick heat from your skin faster (like touching a cold table instead of a wool blanket), so they feel cooler to hold, even if both books are at the same room temperature (Formax Printing).

In summary: porous and fibrous paperback materials trap air and insulate, making the book feel warm, while denser, smoother hardcover materials conduct heat away more efficiently, making them feel cooler.