* Identity and Self-Discovery: The protagonist, David, grapples with his identity and his role in the world. He's constantly questioning his sanity, his place in society, and his connection to reality. The story explores the fragility of identity and the challenges of self-discovery.
* The Nature of Reality: Langan's narrative delves into the question of what constitutes reality. David experiences a series of events that blur the lines between reality and delusion, leaving the reader questioning the nature of truth and perception.
* Isolation and Loneliness: David feels isolated and disconnected from the world around him. His experiences and his mental state lead to a profound sense of loneliness. The story highlights the human need for connection and the pain of isolation.
* The Power of Memory: Memory plays a crucial role in the story, shaping David's understanding of the world and his own identity. The unreliability of memory and its impact on the present are central to the plot.
* The Struggle for Meaning: David's journey is a search for meaning in a seemingly chaotic and meaningless world. He seeks to understand the events that have shattered his life and find purpose in the face of adversity.
* The Nature of Evil: The novel confronts the question of evil and the potential for darkness within human beings. The story explores the consequences of choices and the impact of trauma on the individual.
Ultimately, "Shattered" is a complex and multifaceted novel that explores themes of identity, reality, isolation, and the human condition in a thought-provoking and unsettling way.