Suzanne Leblanc’s The Thought House of Philippa transposes a theory of individuality into a stunningly reflective, sensuous, and frank philosophical novel. Setting the chapters in the various rooms of the house Ludwig Wittgenstein designed for his sister in Vienna, Leblanc’s novel builds an architectural foundation for the main character’s intensely emotional and intellectually acute way of seeing the world and her place in it. Prompted by an experience of isolation early in her life, “P.” (Philippa) moves towards the great world of others and nature—alienated from the everyday and yet devoted to a deeper connection—in an exploration that is profound and moving. Ideas crucial to Wittgenstein’s work—limit, freedom, interior and exterior, self and world—echo and shift in Leblanc’s precise, incantatory prose, propelled through the house’s architecture. The distinct voices of the novel’s four sections act as musical movements, constructed from repetition, variation and development of language, in alternating keys of austerity and splendour. The effect—a pure expression of the passion of clear thought, the adventure of solitude, and the beauty of uncompromising encounter—is utterly riveting. A sui generis experimental novel not to be missed.