In mainstream fiction the dividing line between age groups (MG, YA and adult), because people of different ages clearly enjoy different things. MG might be about coming of age, YA might be about violence and drugs, and adult fiction might be about the relationship between one's career and family.
However, one thing I noticed in fantasy that is different from mainstream fiction is that a lot of things interest both children and adults alike. There is, somehow, far more common interests between young and old when it comes to the speculative, when compared to the realistic. While a story about a dad trying to juggle his work and family life might be of little interest to a 12 year old, unicorns, dragons, mages and wars seem to interest everyone from 8 year olds to 40 year olds. In fact, I can't really find what distinguishes the many genres. Take His Dark Materials -- they could've been kid's books minus a few borderline bloody scenes, or an adult's book. In fact, I'm pretty sure the anti-religious background of the book will only be picked up by an adult. Or take the Magic Kingdom series by Terry Brooks. Minus the lawyer protagonist and the romance, and make the protagonist a 12-year-old trying to become a young king instead, and most of the novel could've remained unchanged, and fashioned into a MG novel instead.
So my question here is: what exactly does the different age groups demand in terms of subject matter? Or is it mostly stuff like age of protagonist, vocabulary, length, etc.?
However, one thing I noticed in fantasy that is different from mainstream fiction is that a lot of things interest both children and adults alike. There is, somehow, far more common interests between young and old when it comes to the speculative, when compared to the realistic. While a story about a dad trying to juggle his work and family life might be of little interest to a 12 year old, unicorns, dragons, mages and wars seem to interest everyone from 8 year olds to 40 year olds. In fact, I can't really find what distinguishes the many genres. Take His Dark Materials -- they could've been kid's books minus a few borderline bloody scenes, or an adult's book. In fact, I'm pretty sure the anti-religious background of the book will only be picked up by an adult. Or take the Magic Kingdom series by Terry Brooks. Minus the lawyer protagonist and the romance, and make the protagonist a 12-year-old trying to become a young king instead, and most of the novel could've remained unchanged, and fashioned into a MG novel instead.
So my question here is: what exactly does the different age groups demand in terms of subject matter? Or is it mostly stuff like age of protagonist, vocabulary, length, etc.?