This monograph collects the complete fifteen-paper Inverted Hypersphere Cosmology as of the current version date. Figures are not included in this version (IHC) series into a single volume, organised for logical flow from foundational axiom to experimental predictions. The entire framework derives from one axiom: the pre-geometric state is a non-preferential void — no direction, scale, or configuration is preferred. This single requirement uniquely selects real projective four-space (RP⁴ = S⁴/ℤ₂) as the topology of the universe, with no additional assumptions and zero free parameters. From this axiom alone, the following are derived in full: COSMOLOGICAL SECTOR • Dark energy density: Ω_Λ = 0.6889 (Planck 2018: 0.6847 ± 0.0073) • BAO sound horizon: r_s = 153.2 Mpc (CAMB/Planck: 147.78 Mpc) • Cosmological constant problem resolved via geometric seesaw: ρ_Λ² = ½ ρ_UV |ρ_IR| • H₀ tension addressed through RP⁴ shell-crossing at z = 0.754 • DESI DR2 dynamical dark energy signal predicted as topological shell crossing, not phantom crossing • Friedmann equations derived from RP⁴ topology (not assumed as input) STANDARD MODEL MASS SPECTRUM • Charged lepton masses (e, μ, τ) to < 0.06% with zero free parameters • Proton/electron mass ratio: 4 × 27 × 17 = 1836 (0.008% from observed) • Neutron–proton mass difference: 1.289 MeV (0.34% from observed) • Complete quark mass spectrum from φᵏ shell hierarchy • QCD confinement scale: Λ_QCD = 305 MeV (8% from PDG) • Strong-CP problem resolved: RP⁴ topology forces θ_QCD = 0 exactly GAUGE STRUCTURE • Gauge group SO(10) derived as a mathematical consequence of RP⁴ topology • Three fermion generations from ℤ₃ triality of SO(8) • Weinberg angle: sin²θ_W = 3φ⁻¹/8 = 0.23176 (PDG: 0.23122) • Fine structure constant: α⁻¹ = 137.036 (error 3.5 × 10⁻⁸) • Base-24 arithmetic identified as the natural language of IHC The monograph is structured in five parts: Part I — Foundations (Prequel, GR derivation, Companion Proofs) Part II — Cosmological Structure (Papers I–III, DESI) Part III — Gauge Structure and Unification (GUT, Base-24) Part IV — Standard Model Mass Spectrum (Papers IV–VII) Part V — Synthesis (Complete Lagrangian, Unified) All 15 papers are included at full length with a unified bibliography (112 entries). The complete Lagrangian and a unified single-paper summary are included as the final two chapters.