"Mythology" covers all the major and most minor Greek, Norse and Roman gods, goddesses, stories and locales. Edith Hamilton makes no pretenses that this is all there is to say on mythology, but she gives a reader a fine start.
Hamilton puts them into sensible structures so beginners can learn in a context which are easy to understand. She provides major section titles helping readers get straight to the required story, like "Stories of Love and Adventure" You'll find "Cupid and Psyche" as a chapter.
Chapters are named mostly by story like, "The Trojan War."
She quotes from the sources, so the reader knows how it is she got her information.
Character-driven in format, readers can look up a name, find the subtitle with that name, and read why that character matters. She writes narratively, sounding a little like "Cliff's Notes." This is a good thing, because the poetry from which these myths are drawn can be overwhelming.
Nicely organized is the geneological table section. It looks like a family tree, in a English royalty kind of way.
As a writer, I use it for a quick reference guide. I usually only need a few nuggets of information, and she gives me plenty. I first acquired it high school, using it to get out of those tough jams when I did not understand books like "The Odyssey," by Homer.
More than mere reference, "Mythology" is good reading for no other purpose than serendipitous curiosity.
I fully recommend it.