Cozy fantasy is a low-stakes, comforting kind of fantasy about community, food and gentle adventures; learn its traits, popular books and where to start.

Romantasy combines romance and fantasy, with a love story at the center of a magical world and a happy ending; learn the tropes, examples and why it has become a publishing phenomenon.

Young adult books center on teen characters and experiences, while new adult books follow characters aged about 18 to 25; learn the differences in age, themes, content and where each is shelved.

Novels are 40,000 words or more, novellas run about 17,500 to 40,000, and novelettes 7,500 to 17,500; see the word counts, famous examples and why the labels matter.

A Lexile level measures reading ability and text difficulty; learn what the numbers mean, how to find your child’s Lexile from school tests, and how to pick books in their range.

Most experts suggest 15 to 30 minutes of reading a day for children, with read-alouds for younger kids; see time suggestions by age and tips for building the habit.

There is no official number of books a child should read a year, but guidelines suggest daily reading and a range of about 20 to 100 books depending on age and book length.

Reading on an e-ink Kindle does not damage your eyes, though any screen can cause temporary strain; learn what the evidence says and how to read comfortably.

The Bible is usually cited as the best-selling book of all time, followed by classics such as Don Quixote and series such as Harry Potter; see estimates and how they differ.

No one can measure exactly which book is read most, but religious texts and a few classics top most estimates; here is how estimates are made and where they fall short.