Abstract: A fire and smoke detector utilizes a statistical analysis of the near infrared radiation incident on it. The spectral radiation intensities incident on the fire detector are continuously measured at two near-infrared wavelengths, and a time series of apparent source temperatures is obtained from these measurements. The power spectral density and the probability density function of the apparent source temperatures are sufficient to determine the presence of a fire in the vicinity of the detector. The detector can indicate the presence of a fire in an adjoining room from the radiation which is incident on it due to reflections from common building materials. The present invention relates to fire and/or smoke detection methodology and associated apparatus. The detector utilizes fiber optic as a viewing and absorption/scattering detection means.