Matthew Helmke has used Ubuntu since 2005. He has written about Linux for several magazines and websites, is a lead author of The Official Ubuntu Book and Ubuntu Unleashed. He also coauthored A Practical Guide to Linux: Commands, Editors, and Shell Programming; VMware Cookbook; and a Practical Guide to Fedora and RHEL, 8e. In his day job, Matthew has worked for Canonical, makers of Ubuntu; for Red Hat, one of the largest and oldest open source software companies; and today works for a Silicon Valley startup called Gremlin (https://www.gremlin.com).
Matthew first used UNIX in 1987, while studying Lisp on a Vax at the university. He has run a business using only free and open source software, has consulted and done contract work, and teaches as an adjunct instructor for the University of Arizona. You can learn more about Matthew at https://www.linkedin.com/in/matthewhelmke/ or drop him a line with errata or suggestions at email@example.com.