This is a descriptive (readme) file accompanying the article: Green, W. A. G. Hunt, S. L. Wing, and W. A. DiMichele (2011) Does extinction wield an axe or pruning shears? How interactions between phylogeny and ecology affect patterns of extinction. Paleobiology 37(1):72--92. This file is electronic supplement 1 (of 2). Electronic supplement 2 is a compressed tarball providing the data, necessary R functions, and scripts to run the models described in the paper and to produce the raw figures derived from the model output. It was created with tar -cvz and can be uncompressed on a unix-flavored system with tar -xvf. The uncompressed tarball includes two R scripts, a directory with 4 R functions used in the scripts, and a data directory providing the output of a run of the first script (FinalModelRuns.R) and all additional data needed to for producing the raw figures shown in the article (which are created by the second script (MakeFigs.R). Any questions should be addressed to Walton Green (wagreen@bricol.net).