A techno-thriller is a type of book that combines a thrilling story with technology. It usually features a character who is an expert in technology, like a computer hacker, who uses their knowledge to try to solve a difficult problem or escape from a dangerous situation. The story usually has a lot of suspense and danger, just like a regular thriller, but the added element of technology adds a unique twist. An example of a popular techno-thriller is the novel "The Girl With the Dragon Tattoo" by Stieg Larsson.