We work with the Reuters-RCV1 collection as our model collection in this chapter, a collection with roughly 1 GB of text. It consists of about 800,000 documents that were sent over the Reuters newswire during a 1-year pe-riod between August 20, 1996, and August 19, 1997. A typical document is shown in Figure 4.1, but note that we ignore multimedia information like images in this book and are only concerned with text. Reuters-RCV1 covers a wide range of international topics, including politics, business, sports, and (as in this example) science. Some key statistics of the collection are shown in Table 4.2.