I was asked to review a book, titled "The Phenomena in [kind of physics]". I responded that the leading "The" should be removed from the title. However, when the author, a non-native speaker, asked me if I could explain why the title as given was erroneous, I had no idea. What rules of grammar does the title violate? If none, why does it sound wrong?
Using the definite article (the) in that situation suggests the title refers to pre-specified phenomena. That will leave native speakers asking "which phenomena?"
Omitting the definite article makes the title general, referring to all phenomena.
Compare these two sentences:
"You smell like yoghurt." General comment. Consider washing.
"You smell like the yoghurt." Which one? This strawberry yoghurt? That's not so bad.
In the case of book titles like the one mentioned above, there isn't normally an intention to distinguish between different known groups that we know the reader has already come across and which we fear the reader may confuse - which would demand "The".
On the contrary, the intention is usually simply to state "This is What's Inside!", and no definite article is used in such cases. Like items listed on a menu in a restaurant we've just walked into, or like labels on containers of food items in the supermarket, the intention in such book titles is simply to inform us of what we will find within: some, perhaps all, of those items. No article is used with plural nouns in such cases: "Baked Beans" written on a tin, "Mussels cooked with white wine" on a menu, "Border Collies" as a book title about that breed of dog.
If we think about adding "The" in these cases, it does sound very weird because that's not how we present a 'label' indicating contents.
There are cases when both options are possible with a subtle difference. Let's take two books: "Castles of Spain" vs "The Castles of Spain". The former states simply that it is about these items. The latter draws us a little more into the subject matter. It does this, I believe, by creating a scenario where we are assumed to have knowledge of a) other castles in other countries and b) other items in Spain besides castles. Besides this, 'The' also expresses that it's a comprehensive look at Spanish castles, whereas the former usage without the definite article leaves that open.