Tom Limoncelli is an American system administrator, author, and speaker. A system administrator and network engineer since 1987, he speaks at conferences around the world on topics ranging from firewall security to time management. He is the author of Time Management for System Administrators from O'Reilly; along with Christine Hogan, co-author of the book The Practice of System and Network Administration from Addison-Wesley, which won the 2005 SAGE Outstanding Achievement Award, and in 2007 with Peter H. Salus he has published a compilation of the best April Fools jokes created by the IETF entitled The Complete April Fools' Day RFCs.