We thank Robert Harper, Brian Noble, Daniel Jackson, Edo Biagioni, Greg Morrisett, Scott Draves, Chris Colby, Martin Abadi and Dave Detlefs for reading previous versions of this paper and for suggesting many improvements. We also thank Charles Garrett, Brian Bershad, Wilson Hsieh for suggesting many improvements to the methodology for the Modula-3 performance measurements. Finally, we thank the anonymous reviewers for their many suggestions for improving this paper. In particular we thank our shepherd, Jay Lepreau, who also suggested the PCC name.