The novel centers around a woman named Anna Wulf, a writer who keeps four notebooks, each representing a different aspect of her life: her experiences in Africa, her current life in London, a novel she is writing, and her personal experiences. As Anna's mental state deteriorates, she attempts to unify her fragmented self in a fifth notebook, the golden notebook. The novel explores themes of mental breakdown, communism, the changing role of women, and the fear of nuclear war.

"I Capture the Castle" is a coming-of-age novel that tells the story of 17-year-old Cassandra Mortmain and her eccentric family living in a dilapidated English castle during the 1930s. Cassandra's father is a reclusive writer suffering from writer's block and her stepmother is a bohemian artist. The family's life changes dramatically when two American brothers inherit the estate. The novel, written in diary format, explores themes of love, poverty, and the transition from adolescence to adulthood.

The book is a humorous and touching glimpse into the life and mind of a British adolescent boy, navigating the challenges of teenage life. Written in diary format, the protagonist grapples with everything from acne, unrequited love, school bullies, family issues, and his aspirations of becoming an intellectual. His misinterpretations of the adult world around him, coupled with his overly serious and introspective nature, provide plenty of comedy and make for an endearing and relatable coming-of-age story.

The book is a humorous and honest portrayal of a single woman's life in London. The protagonist, a 30-something year old woman, struggles with her weight, smoking, and alcohol consumption, all while trying to navigate her love life and career. The story is told through her personal diary entries, which include her daily calorie counts, number of cigarettes smoked, and other personal anecdotes. It's a modern take on romantic relationships and self-improvement, with a healthy dose of comedy.