Electronic Material accompanying R. E. Kopp (2007), The Identification and Interpretation of Microbial Biogeomagnetism. Ph.D. Thesis, Division of Geological and Planetary Sciences, California Institute of Technology. Copyright (C) 2007 by Robert E. Kopp **** Three software packages accompany this dissertation. matFMR-1.1 provides MATLAB functions for analyzing ferromagnetic resonance spectra. The usage of these functions is described in the accompanying README.txt file. matRockmag-1.0 provides MATLAB functions for analysis of rock magnetic data produced by a Caltech-style 2G magnetometer setup. The usage of these functions is described in the accompanying README.txt file. Paleomag2007-2.3.3 is the Visual Basic 6 control software for a Caltech-style 2G magnetometer sample changer, as described in Appendix II. The installation of this code is described in the accompanying README.txt file. The usage of the code is described in the accompanying Paleomag 2006 Manual.pdf. In addition, the data files collected and analyzed in Chapters 2-5 are also included. FMR data are contained in paired .asc and .par files, while rock magnetic data is contained in .rmg files. These files can be analyzed using matFMR and matRockmag, respectively. They are plain text files and can readily be imported into other software programs as well.