The book is made up of two narrative streams, interwoven with alternating chapters. The names of the chapters indicate which stream they belong to: one set are numbered forward (One, Two...) in words, the other in reverse (XIII, XII...) with Roman numerals. The story told by the former moves forward chronologically (as the numbers suggest) and tells a self-contained story while in the latter each chapter is successively earlier in Zakalwe's life and provides illuminating episodes. Further complicating this structure is a prologue and epilogue set at another time entirely and many flashbacks within the chapters.
Banks wrote a much longer version of the book with a much more conventional structure long before any of his books was published. The book's cryptic Acknowledgement credits another science fiction author, Ken MacLeod, with the suggestion "to argue the old warrior out of retirement" (which means the suggestion to rewrite the old book) and further credits him with suggesting "the fitness program" (the new structure...MacLeod's own books often use dual time streams).