Classic books are generally considered to be those that have stood the test of time, holding enduring literary and cultural significance. They are often praised for their quality of writing, exploration of universal themes, and lasting influence on readers and other writers. While the term can apply to books of any genre and time period

Fiction books are literary works that are not based on real events or people, but rather are products of the author's imagination. They include novels, short stories, and novellas, and often feature invented characters, settings, and plots

Nonfiction books are works that aim to convey information about the real world, based on facts and real events, rather than being fictional stories. They differ from fiction, which uses imagination to create invented characters and events.

"Research books" typically refers to books used as source material for research. They contain information, data, or analysis that contributes to a particular research project or study. Essentially, they are books that researchers consult to find information relevant to their work. These books can be academic texts, historical accounts, or any other type of publication that provides valuable insights for research purposes.

Academic books, also known as scholarly books, are publications written by experts or scholars with the primary goal of advancing knowledge within a specific academic field. They are typically written for an audience of researchers, academics, and advanced students and often feature in-depth analysis, research findings, and theoretical frameworks.

"Kids books" is a broad term encompassing literature created for young audiences, typically ranging from infants to teenagers. This includes picture books, chapter books, and young adult novels, both fiction and nonfiction. Children's books are often characterized by engaging illustrations, age-appropriate language, and content that entertains or educates.