Looking for a book

So at the end of work today we started talking about different countries, cultures, ethnicities and races. All very confusing stuff for me. I have been discussing this topic with many Americans since my freshman year in college.

I was saying that I knew a Guatemalan girl who looked Asian, but did not claim Asia whatsoever as a nationality, race or heritage. She was born and raised in Guatamala, her mother tongue is Spanish and she participates in Guatemalan culture. A co-worker said Asian is her "ethnicity." And I had to ask myself once again "What is ethnicity?" Or do I even know what that means? Does a person decide what their ethnicity is? Or do people decide the ethnicity of someone based on they way they look and if so is this what "race" is? I am not sure myself.

A couple of other examples:

I worked with a girl from Jamaica and she said people would always refer to her as "African American" and she didn't like it because she wasn't American, she was Jamaican. So is her ethnicity African even though she identifies with Jamaican Culture?

Friends from Spain were here filling out paper work which asked their race/ethnicity and she asked me "Do I check caucasian? or Do I check hispanic? She is whiter than me (as most Spaniards are, even though people do not believe me) and she speaks Spanish but it is not her mother tongue. If you google ethnic groups of Spain they list Basque, Catalan, Galician, etc. So within each country there ethnic groups that Americans don't even refer to. Hi Anna!

What race/ethnicity are people from Brazil? I know they have a lot of ethnicities within their own country. But to the American, what ethnicity is a Brazilian? The national language is portugeuse, they have many natives (indigenous), blacks, and are surrounded by a largely (hispanic?) population. I put a question mark next to hispanic, because what is Hispanic? I think that Brazilians living in American are often referred to as "Latino" or "Hispanic" but I think this may be incorrect as they do not speak Spanish and their ancestors are not from Spain.

What is my race/ethnicity? My great Aunt has a family tree/recipe book that says my great great great grandfather is Moroccan. My dad's family comes from Poland, France, Ireland, and Russia. But those are all nationalities...can they be ethnicities too? Or can I reach further and have an ethnicity from all the Countries listed? Or since I don't identify with those countries, am I without Ethnicity? Is my ethnicity "American" because I largely identify with American culture? Or is it just my nationality?

What about natives from Mexico that don't speak Spanish but rather the Indigenous languages such as Nahuatl. Are they Hispanic? Language lesson: Nahuatl is the language where words like "Chipotle" and names like "Xochitl" come from. NO Chipotle is NOT Spanish.

Anywho, if anyone knows a good book they can recommend, send it my way. The web is no help. I need something serious, not just blogs. This is one giant question and not intended to hurt anyone. I don't have sited sources, and this is not a literary masterpiece...just my own random questions.

Thanks for reading. Crafting to come.