I'm giving this book four stars because I personally enjoyed it, for the most part. However, I think many readers will find the book off-putting, and I would therefore not recommend it to the average reader (if there is such a thing). Two reasons for this: First, the subject matter, which mostly involves Roubaud's education and career as a mathematician. Unless you have some knowledge of modern mathematics (formalism, the Bourbaki movement, etc.) a good part of the narrative will likely be difficult to take in. Second, Roubaud's elliptical style of writing (frequently nested parentheses, interpolations and bifurcations, along with two different type-font sizes) will present a discordant and jarring reading experience for those expecting to read a novel, which this most assuredly is not (despite its subtitle). For someone with some acquaintance with modern mathematics and a willingness to wade through some very "creative" (if not downright chaotic) writing, this book will be overall an enjoyable experience as it was for me.
One thing that makes this work endearing is the personality of its author: Roubaud is so lighthearted and likeable, you want him as your friend. Here is a fascinating, multi-talented senior French intellectual of wide-ranging interests who takes life as an adventure, never complains, and never stops growing. Half-way through the book I fell in love with him, and that is what primarily kept me going. The book is a part of a multi-volume memoir called "the great fire of london", which is a reminiscence of the author's life, centering around a Project (a mathematical work together with a novel) which he had planned to complete, entitled The Great Fire of London. This multi-volume memoir is thus a journey through memory coupled with imagination, as Roubaud tries to come to terms with his failure to realize this great Project of his, and retraces the course of his life. Reviews of the book call it Proustian, mainly because of Roubaud's frequent reflections on the role of the imagination in memory, and how memory-images frequently bear no relation to what really happened because the imagination colors and distort so much of our past experience. These reflections occur frequently throughout the book, which is written entirely in the first-person singular.
I have several pieces of advice to potential readers: First, if you do decide to tackle this book, you may want to first read Amir Aczel's book, "The Artist and The Mathematician", since it will give you the mathematical background you will need to enjoy Roubaud's book. Secondly, scattered throughout the texts are "redirections" (right-pointing arrows, with section numbers afterwards). I have read various reviews saying you're "supposed" to read the book by following these redirections. For the interpolations, that is fine (they are basically like footnotes, gathered at the end of each chapter (they are generally more imaginative than the chapters themselves)) (But beware that there are a few interpolations nested within interpolations!). Then there are two chapter-sized bifurcations as well. Following the bifurcations in this way will lead you into some rather deep, swampy grasslands since a redirection to bifurcation B is nested within bifurcation A. There are also scattered about the text redirections to different "branches" (or volumes) of the memoir/project. In my opinion, you are far better off just reading the book in the traditional linear way, not jumping around.