Potpourri of comments about the fiber optic gyro for its 40th anniversary, and how fascinating it was and it still is!

This 40th anniversary is the opportunity to recall how fascinating is the fiber-optic gyro with its potential perfection. Pure unaided strapdown inertial navigation yielding drift of less than one nautical mile in a month has been demonstrated in a laboratory. This paper also adds several comments about points that could be better known and should be outlined.