The paper discusses the holographic principle in Anti-de Sitter (AdS) space, showing how the holographic bound—limiting information to one bit per Planck area—is a natural consequence of the correspondence between AdS space and a boundary conformal field theory (CFT). The key idea is the "IR-UV connection," where infrared effects in the bulk AdS space correspond to ultraviolet effects in the boundary CFT. This connection explains why the holographic bound is necessary for the correspondence to hold. The paper begins by introducing the holographic hypothesis, which posits that a quantum theory with gravity can be described by a boundary theory without gravity. It then discusses the AdS/CFT correspondence, where a bulk supergravity theory in AdS space is dual to a boundary super Yang-Mills theory. The challenge is to justify the holographic bound, which limits the number of degrees of freedom in the boundary theory. The paper explains that the IR-UV connection is crucial for understanding the holographic bound. Infrared divergences in the bulk theory correspond to ultraviolet divergences in the boundary theory. This connection is demonstrated through various examples, such as the behavior of propagators and the energy of strings in the bulk theory. The paper also discusses the information storage capacity of the boundary theory, showing that introducing a cutoff in the boundary theory corresponds to a short-distance regulator in the bulk theory. This leads to the conclusion that the number of degrees of freedom in the boundary theory is proportional to the area of the boundary, consistent with the holographic bound. The paper concludes with general remarks on holography in AdS space, emphasizing the dramatic effects of holography, such as the drastic reduction in the number of degrees of freedom per unit volume. It also notes that the holographic principle may be extended to theories with zero or positive cosmological constants, though this requires new ideas. The paper is supported by references to previous work on the AdS/CFT correspondence and the holographic principle.The paper discusses the holographic principle in Anti-de Sitter (AdS) space, showing how the holographic bound—limiting information to one bit per Planck area—is a natural consequence of the correspondence between AdS space and a boundary conformal field theory (CFT). The key idea is the "IR-UV connection," where infrared effects in the bulk AdS space correspond to ultraviolet effects in the boundary CFT. This connection explains why the holographic bound is necessary for the correspondence to hold. The paper begins by introducing the holographic hypothesis, which posits that a quantum theory with gravity can be described by a boundary theory without gravity. It then discusses the AdS/CFT correspondence, where a bulk supergravity theory in AdS space is dual to a boundary super Yang-Mills theory. The challenge is to justify the holographic bound, which limits the number of degrees of freedom in the boundary theory. The paper explains that the IR-UV connection is crucial for understanding the holographic bound. Infrared divergences in the bulk theory correspond to ultraviolet divergences in the boundary theory. This connection is demonstrated through various examples, such as the behavior of propagators and the energy of strings in the bulk theory. The paper also discusses the information storage capacity of the boundary theory, showing that introducing a cutoff in the boundary theory corresponds to a short-distance regulator in the bulk theory. This leads to the conclusion that the number of degrees of freedom in the boundary theory is proportional to the area of the boundary, consistent with the holographic bound. The paper concludes with general remarks on holography in AdS space, emphasizing the dramatic effects of holography, such as the drastic reduction in the number of degrees of freedom per unit volume. It also notes that the holographic principle may be extended to theories with zero or positive cosmological constants, though this requires new ideas. The paper is supported by references to previous work on the AdS/CFT correspondence and the holographic principle.