Superimposition means seeing something as it is not or seeing something as something else. Superimposition creates illusions that one thing is what it is not. Superimposition is mistaking that a thing has an attribute that it doesn't have. Superimposition is an error.

Illusions can be used to explain Superimposition:
A rope appears to be a snake. [Perceptual Illusion].
Hot air current moving over faraway sand dunes appears to be a lake. [Optical Illusion].
The rising moon at the horizon appears to be larger than the overhead moon. [Perceptual Illusion].
The color of Light is White Yet the sky appears blue-colored. [Optical Illusion].

These examples are inadequate but are the best pointers in the direction of the Truth: The Body-Mind-World superimposes Brahman and obscures Reality. Believing the Body-Mind-World to be the Truth is caused by the Ignorance of Brahman. Knowledge of Brahman naturally eradicates Ignorance. That is the purpose of this Book: It's a rope, not a snake! This book goes hand in hand with the other book: Waking Dreaming Sleeping Being: Swapna Nidra Gnyana Sadhana. May the knowledge from the books serve you well!