From the introduction:
[In] Thunderball...Every interaction is contained within a series of programmed Adventure Paragraphs that are organized by numbered sections. Each section describes what is happening to your character, where they are, with whom they are interacting, and what choices are available.
Unlike a novel, the sections are mixed up so that you cannot read this book from front to back. You should not attempt to read the sections in numerical order. To do so would not make sense and could spoil the fun of the adventure. Instead, at the end of each section there is a pointer to the next section in the story line based on the choices your character makes or the consequences of the actions found within this section.
While based on the movie Thunderball, some of the NPCs’ backgrounds and the basic plot points have been modified to keep you from anticipating events in the adventure and to maintain an element of surprise. Following along with the movie could result in pursuing a false lead…or in having a very short career at M.I.6.
You may play the role of James Bond (the adventure is designed for that) or you may play a character of your own creation, either a Rookie, an Agent, or a “00” rank.