Next: Methods for Structuring and Searching Very Large Catalogs . ... We have explored two automated classification methods: supervised classification using Artificial Neural Networks (ANN) and unsupervised classification using Self Organized Maps (SOM). These methods are used to classify IUE low-dispersion spectra of normal stars with spectral types ranging from O3 to G5. This paper describes the application of automated methods to the problem of the classification of stellar spectra. ...