This document provides an overview of natural language processing (NLP) for text categorization and classification. It discusses supervised and unsupervised learning problems and classification algorithms like Naive Bayes and support vector machines (SVM). Specific applications mentioned include email classification, spam filtering, and document organization. The document compares Naive Bayes and SVM, noting that Naive Bayes is easier and faster while SVM is more difficult but can handle binary classification problems.