The book Neo hides his computer discs in is called "Simulacra and Simulation" (French: Simulacres et Simulation), a philosophical treatise by Jean Baudrillard seeking to interrogate the relationship among reality, symbols, and society.
The chapter where they’re hidden is called “On Nihilism”.
Simulacra are copies that depict things that either had no reality to begin with, or that no longer have an original. Simulation is the imitation of the operation of a real-world process or system over time.
'…The simulacrum is never that which conceals the truth—it is the truth which conceals that there is none. The simulacrum is true.'