He is noted for his work on quantum mechanics (particularly the many-worlds interpretation-the Everett interpretation), on identity and indiscernibility in physics, and on structural realism.

Saunders was an early graduate of the Physics and Philosophy undergraduate degree at the University of Oxford.

[1] Saunders was an early champion[2] of 'structural realism', the view that mature physical theories correctly describe the structure of reality.

[7] Saunders has also been a central figure in recent debates over identity and indiscernibility in physics[citation needed].

[11] In addition, Saunders has worked on quantum field theory, on the philosophy of time, and on the history of physics; he has written numerous encyclopaedia articles and book reviews.