I’ve been looking a bit into mythology (mainly Greek) for fun in the past month or so and I thought it would be interesting to read an old text/actual source (instead of just Wikipedia). I’ve stumbled into the existence of “Bibliotecha Historica” compiled/written by Diodorus Siculus. It sounds extremely interesting to me and I really like the premise of the ancient author having compiled the history and mythology he has seen/heard from around him. I do, however, fear that maybe it will be a bit misleading for someone like me who honestly doesn’t know a lot about the subject, as it seems that he has been very harshly criticised over the years. Do I need to already know a lot about the subjects he discusses or can I just jump right in blindly and casually?
I do not think it is too bad but it also would not be what I recommend if this is your first go at classical texts. It is a bit dry, and even its "mythological" section is written as a history/geography rather than a collection of stories.
If you like mythology and want to read the stories, the best option is going to be Ovid's Metamorphoses as long as you don't mind verse (although there are probably prose translations out there). It is the source of a lot of the myths that we have today and perhaps the closest thing to a "book of mythology" from the ancient world.