Maybe it's about the hidden aspects of human nature. A shadow can represent what is hidden or not fully visible. In the novel, it might explore the parts of people that they keep in the dark, like their secrets, fears, or unspoken desires. This could be the main theme that runs throughout the story, showing how these hidden elements affect the characters' lives and relationships.
It could be about the transience of life. Just as a shadow passes quickly, perhaps the events and characters in the novel are a representation of how fleeting life is and how things can pass by without leaving a strong mark.
The main theme might be related to the elusiveness of reality. A shadow is not a solid, definite thing but rather an impression. In the 'passed like a shadow novel', it could be that the author is trying to convey how reality can be like a shadow, difficult to fully understand or hold on to. The characters may be constantly chasing after something that is as intangible as a shadow, be it truth, love, or a sense of purpose.
The main theme is often considered to be about the power of literature. It shows how books can shape lives, hold memories, and have a lasting impact on individuals and society.
In 'Library of Light and Shadow: A Novel', the main theme could potentially be the journey of self - discovery. The contrast between light and shadow can symbolize the different aspects of a person's self. The characters might be on a quest to understand their true selves, facing both the bright and dark parts within. They may have to navigate through their own personal 'library' of experiences, which are filled with moments of light (happiness, success) and shadow (sadness, failure), in order to find their place in the world.
The main theme could be about identity. Without a shadow, the man might be seen as lacking a certain aspect of his being that is typically associated with having a complete physical presence. It could also explore themes of isolation, as being different in such a fundamental way might set him apart from others.
One of the main themes could be power. The idea of conquering implies a pursuit of power, and the story might explore how characters obtain, use, or are corrupted by power.
The main theme could be about the duality of human nature. The shadow often represents the hidden or darker side of a person in many short stories.
One book that might be similar is 'The Great Gatsby'. It also has elements of mystery and a somewhat shadowy atmosphere in terms of the characters' hidden desires and pasts. Another could be 'Wuthering Heights', with its complex relationships and a sense of something lurking beneath the surface, much like a shadow. And 'Dracula' has a dark, shadowy feel to it with the presence of the vampire which is often associated with the unknown and the hidden in the shadows.
I'm not sure specifically as I haven't read it in detail, but generally, in many novels with 'light and shadow' in the title, themes could be about contrast, like the contrast between good and evil, or different aspects of a character's personality.
The 'A Raven's Shadow' series seems to focus on themes like destiny and the struggle against evil. The heroes are constantly challenged to fulfill their fate and overcome powerful antagonists.
The main theme could be about identity. Without a shadow, the man is lacking something that is usually considered a natural part of a person. It might also touch on themes of isolation as he is different from others who have shadows.
I think it might center around the idea of finding light in the midst of darkness or vice versa. Maybe it also delves into the blurred lines between good and evil. These themes often add depth to a story like this.