The first year data from the Wilkinson Microwave Anisotropy Probe (WMAP) provides strong evidence for the standard cosmological model, a flat universe dominated by dark energy with nearly scale-invariant adiabatic Gaussian fluctuations. The best-fit parameters from WMAP data alone are h = 0.72 ± 0.05, Ω_bh² = 0.024 ± 0.001, Ω_mh² = 0.14 ± 0.02, τ = 0.166 ± 0.071, n_s = 0.99 ± 0.04, and σ₈ = 0.9 ± 0.1. When combined with other data, such as the ACBAR and CBI experiments, 2dFGRS, and Lyman α forest data, the best-fit parameters are h = 0.71 ± 0.03, Ω_bh² = 0.0224 ± 0.0009, Ω_mh² = 0.135 ± 0.009, τ = 0.17 ± 0.06, n_s = 0.93 ± 0.03, and σ₈ = 0.84 ± 0.04. These parameters imply a universe age of 13.7 ± 0.2 Gyr. The model is consistent with other astronomical measurements, including the age of the universe, the baryon/photon ratio, and the Hubble constant. The model also favors a slowly varying spectral index, though the significance of this running index is sensitive to uncertainties in the Lyman α forest. Combining WMAP data with other data constrains the universe's geometry to Ω_tot = 1.02 ± 0.02 and the dark energy equation of state, w < -0.78 (95% confidence limit). The combination of WMAP and 2dFGRS data constrains the energy density in stable neutrinos to Ω_νh² < 0.0076 (95% confidence limit), implying a neutrino mass less than 0.23 eV (95% confidence limit). The WMAP detection of early reionization rules out warm dark matter. The model is consistent with the cosmic microwave background, large-scale structure, and supernova data, and provides strong constraints on the universe's parameters. The results support the standard cosmological model and provide important insights into the nature of dark energy and the early universe.The first year data from the Wilkinson Microwave Anisotropy Probe (WMAP) provides strong evidence for the standard cosmological model, a flat universe dominated by dark energy with nearly scale-invariant adiabatic Gaussian fluctuations. The best-fit parameters from WMAP data alone are h = 0.72 ± 0.05, Ω_bh² = 0.024 ± 0.001, Ω_mh² = 0.14 ± 0.02, τ = 0.166 ± 0.071, n_s = 0.99 ± 0.04, and σ₈ = 0.9 ± 0.1. When combined with other data, such as the ACBAR and CBI experiments, 2dFGRS, and Lyman α forest data, the best-fit parameters are h = 0.71 ± 0.03, Ω_bh² = 0.0224 ± 0.0009, Ω_mh² = 0.135 ± 0.009, τ = 0.17 ± 0.06, n_s = 0.93 ± 0.03, and σ₈ = 0.84 ± 0.04. These parameters imply a universe age of 13.7 ± 0.2 Gyr. The model is consistent with other astronomical measurements, including the age of the universe, the baryon/photon ratio, and the Hubble constant. The model also favors a slowly varying spectral index, though the significance of this running index is sensitive to uncertainties in the Lyman α forest. Combining WMAP data with other data constrains the universe's geometry to Ω_tot = 1.02 ± 0.02 and the dark energy equation of state, w < -0.78 (95% confidence limit). The combination of WMAP and 2dFGRS data constrains the energy density in stable neutrinos to Ω_νh² < 0.0076 (95% confidence limit), implying a neutrino mass less than 0.23 eV (95% confidence limit). The WMAP detection of early reionization rules out warm dark matter. The model is consistent with the cosmic microwave background, large-scale structure, and supernova data, and provides strong constraints on the universe's parameters. The results support the standard cosmological model and provide important insights into the nature of dark energy and the early universe.