1. A method of non-invasively deriving a measure of the concentration of glucose in a human body fluid comprising the steps of: (a) irradiating a human body tissue containing said human body fluid with monochromatic light in the near infrared spectral region emitted by a monochromatic light source, thereby causing said glucose within the irradiated human body tissue to produce Raman scattering of said monochromatic light into multiple, spatially separated, frequency shifted wavelength components associated with molecular characteristics of said glucose; (b) tracking variations in light emitted by said monochromatic light source; (c) directing said multiple, spatially separated, frequency shifted wavelength components resulting from said Raman scattering through a holographic notch filter, which removes the Rayleigh component of scattered light, onto a photosensitive detector, which produces electrical output signals representative of said multiple, spatially separated, frequency shifted wavelength components associated with molecular characteristics of said glucose; (d) generating ratio signals representative of the ratios of said electrical output signals representative of said multiple, spatially separated, frequency shifted wavelength components resulting from said Raman scattering produced in step (c) to variations in monochromatic light emitted by said monochromatic light source tracked in step (b), so as to eliminate effects of variations of said monochromatic light source; and (e) processing said ratio signals by means of a fuzzy adaptive resonance theory artificial neural network discriminator that has been trained with a plurality of training exemplars, corresponding to scattered light components representative of different concentrations of glucose, and which is robust to a human body fluid sample not previously encountered, and quantitatively deriving therefrom concentrations of said glucose in human body fluid based upon the spectral intensities of detected wavelengths of said spatially separated, frequency shifted wavelength components.