Trained By Her Daddy by Shelly Douglas is a provocative and intense exploration of the themes of power dynamics, forbidden desires, and the complexities of familial relationships wrapped up in a controversial and bold narrative. This book, part of the authors' wider oeuvre of similar themes, delves deep into the psychology of its characters, creating a visceral reader experience that is as unsettling as it is enlightening.

The novel begins with the introduction of its central character, Evelyn, a young woman who returns home after several years of estrangement. Her father, Jonathan, is a compelling and domineering figure whose influence over Evelyn becomes the focal point of the narrative. The title itself, Trained By Her Daddy, might give an indication of the taboo line that the novel will tread. As we move further into the story, it becomes clear that the training referred to is both psychological and physical, wrapped in a guise of paternal discipline and care.

Shelly Douglas, a pseudonym for a duo of writers known for their exploration of taboo and often controversial subjects, has created a world that feels real and raw. The strength of the book lies in its character development; Evelyn, portrayed with depth and nuance, fluctuates between agency and vulnerability. Her emotional and psychological journey through the book is rendered with a sensitivity that compels the reader to empathize with her, despite the challenging nature of the narrative.

The style of Douglas's narration is direct and unflinching. The prose is clean, sharp, and purposefully uncomfortable at times, forcing the reader to confront their own boundaries and biases. The sensory descriptions of the settings intensify the claustrophobic relationship between Jonathan and Evelyn, encapsulating the reader in a tight narrative space that echoes the protagonist’s entrapment.

As the plot unfolds, themes of power, control, and submission are explored not just in the physical sense but also psychologically and emotionally. The dynamics between Evelyn and Jonathan are complex and deeply controversial. Douglas does not shy away from depicting scenes that may provoke a strong reaction, including explicit content and situations that blur the lines of consent. These elements are likely to divide readers—some might find the exploration bold and an important narrative on the extremities of human relationships and desires, while others might see it as overly provocative or distasteful.

One of the critical elements of the novel is its moral ambiguity. Douglas doesn’t provide clear judgements or easy answers, which might be frustrating for some but also serves as a strength of the novel. This ambiguity forces readers to engage more deeply with the text and the uncomfortable questions it raises about authority, dependency, and love.

Moreover, the subplot involving Evelyn’s past and her reasons for estrangement add layers to her character, providing context and depth to her current predicaments. These backstory elements are well integrated, revealing themselves gradually in a way that maintains suspense and emotional impact.

The ending of Trained By Her Daddy is as bold and ambiguous as the rest of the book. Without giving away specifics, it can be said that it stays true to the novel's complex narrative and psychological explorations, leaving the reader with lingering thoughts and questions about the characters and their future. It’s a testament to Douglas’s skill that the conclusion is both satisfying in its narrative weight and open-ended enough to allow different interpretations.

In summary, Trained By Her Daddy is not a book for the fainthearted or those seeking a straightforward narrative. It's a challenging read, both in terms of content and moral exploration. Shelly Douglas has crafted a bold and unapologetic story that delves into some of the darkest corners of human relationships. This book invites, or perhaps dares, its readers to confront their preconceptions and societal taboos. While it may not be universally appealing due to its provocative themes, it offers a piercing look into the complexities of power and submission, love and control, making it a significant, if controversial, addition to contemporary literature on these themes.