This page offers the web documents that are referred to in Chapter 6. In Chapter 3 we discussed pairwise alignment, and then in Chapters 4 and 5 we described how a protein or DNA query can be compared to a database. This chapter covers a series of approaches to multiple sequence alignment, including the popular method of progressive alignment and new methods such as consistency-based and structure-based alignment. We also discuss ways to multiply align long segments of genomic DNA.