Distance sampling refers to a suite of methods, including line and point transect sampling, in which animal density or abundance is estimated from a sample of distances to detected individuals. The book illustrates these methods through case studies; data sets and computer code are supplied to readers through the book's accompanying website.  Some of the case studies use the software Distance, while others use R code. The book is in three parts.  The firstpart addresses basic methods, the design of surveys, distance sampling experiments, field methods and data issues.  The second part develops a range of modelling approaches for distance sampling data.  The third part describes variations in the basic method; discusses special issues that arise when sampling different taxa (songbirds, seabirds, cetaceans, primates, ungulates, butterflies, and plants); considers advances to deal with failures of the key assumptions; and provides a check-list for those conducting surveys.