do you underline or put in quotes the name of a book? What about it's subtitle?

underline a book name and put a poems name in quotes

And what about the subtitle? That also gets underlined? This is for a PowerPoint btw, so does all this still hold true?

for subtitles, do a : and then the subtitle which is also underlined. For powerpoint, I'm not sure, but I would just to be safe. Never hurts.

When formatting the title of a book, it is customary to either italicize it or use quotation marks. Underlining was commonly used in the past when typewriters were the primary means of writing, but it has been largely replaced by italics in modern text formats.

Here are the general guidelines for formatting book titles:

1. Italicization: Italicize the title of a standalone book or a larger work (e.g., a novel, a non-fiction book, or a collection of short stories). For example:
- Pride and Prejudice
- To Kill a Mockingbird
- The Catcher in the Rye

2. Quotation marks: Enclose the titles of shorter works or parts of a larger work (e.g., a chapter, a short story, or a poem) in quotation marks. For example:
- "The Raven" (a poem by Edgar Allan Poe)
- "The Tell-Tale Heart" (a short story by Edgar Allan Poe)
- "Chapter 3: The Forbidden Forest" (from Harry Potter and the Philosopher's Stone)

Regarding subtitles, it is generally preferred to use a colon to separate the main title from the subtitle. Both the main title and subtitle should be formatted the same way. For example:
- The Great Gatsby: A Novel
- The Hunger Games: Catching Fire

Remember to refer to the specific style guide (e.g., MLA, APA, Chicago) recommended by your academic institution or publisher for precise guidelines on how to format titles and subtitles.