These genre pages have proved to be the most challenging of the resource pages because I have to make subjective choices as to what books fit into each category.
So for each one, I have set myself guidelines, which not everyone may agree with.
For the Tragedy page, I have included the books whose main theme portrays human suffering in its many guises, such as poverty, war, abuse, oppression, illness and death, or just unhappiness, loneliness, depression, or lack of satisfaction in life. Many books include a range of emotions, but the ones included here are those in which tragedy is pervasive—either equal to or greater than the other emotional contents. Another guiding factor is the underlying root sentiment upon which the book is based. For instance The Way of All Flesh is filled with caustic humor and is included on the Humor page, but when Butler wrote it, it was an acerbic reaction to his abusive father and abusive Victorian child rearing standards in general. It is tragi-comedy, where both play an equal part. Many books from the Horror page, or the Paranormal page appear here, too, but many do not. The question is, Was the horror written for the sake of horror, or is there an underlying sentiment of human suffering? For this reason, The Island of Dr. Moreau is not included here— it is more of a Sci-Fi thriller, but Frankenstein IS here, because the human emotional issues play such an important role. You may not agree, and in the future I may not either, so of course I always have the option of revisions. But for now these are the books I have included. If you are looking for something in particular, check out all the Cross-Reference/Resource pages. Also, the books listed under Collections contain at least one tragic story.
Incidentally, Wikipedia has an extensive article on Tragedy, in the theatrical sense, and its history from its origin up through the ages. Hope you find this all helpful. Enjoy!