- Gregory, Peter. Solaris Security, Prentice-Hall, 1999. ISBN 0-130-96053-5
- Gregory, Peter. Solaris Security (Japanese Language Edition), Prentice-Hall, 1999. ISBN 4-881-35974-6
- Gregory, Peter. Solaris Security (Chinese Language Edition), Prentice-Hall, 1999. ISBN 7-115-08728-8
- Gregory, Peter. Sun Certified System Administrator for Solaris 8 Study Guide, Prentice-Hall, 2001. ISBN 0-130-40933-2
- Gregory, Peter. Enterprise Information Security, Financial Times Management, 2003. ISBN 0-273-66157-4
- Gregory, Peter. Enterprise Information Security (Romanian Language Edition), Financial Times Management, 2003. ISBN 973-722-043-9
- Gregory, Peter; Miller, Lawrence. CISSP for Dummies, John Wiley & Sons, 2003. ISBN 0-764-51670-1
- Gregory, Peter; Miller, Lawrence. Security+ Certification for Dummies, John Wiley & Sons, 2003. ISBN 0-764-52576-X
- Gregory, Peter. Computer Viruses for Dummies, John Wiley & Sons, 2004. ISBN 0-764-57418-3
- Gregory, Peter; Simon, Mike. Blocking Spam and Spyware for Dummies, John Wiley & Sons, 2005. ISBN 0-764-57591-0
- Gregory, Peter. VoIP Security for Dummies, Avaya Limited Edition, John Wiley & Sons, 2006. ISBN 0-764-03744-X
- Gregory, Peter. SIP Communications for Dummies, Avaya Limited Edition, John Wiley & Sons, 2006. ISBN 0-470-04149-8
- Gregory, Peter. Converged Network Security for Dummies, Avaya Limited Edition, John Wiley & Sons, 2007. ISBN 0-470-12098-9
- Gregory, Peter. IP Multimedia Subsystems for Dummies, Radisys Limited Edition, John Wiley & Sons, 2007. ISBN 0-470-13587-7
- Gregory, Peter. Midsized Communications Solutions for Dummies, Avaya Limited Edition, John Wiley & Sons, 2007. ISBN 0-470-16552-2
- Gregory, Peter. Comunicaciones para Medianas Empresas para Dummies, Edicion Limitada de Avaya, John Wiley & Sons, 2007. ISBN 978-0-470-27666-2
- Gregory, Peter. Unified Communications for Dummies, Avaya Limited Edition, John Wiley & Sons, 2007. ISBN 0-470-17495-1
- Gregory, Peter. Comunicações Unificadas, Edicao Espeçial da Avaya, John Wiley & Sons, 2007. ISBN 978-0-470-27690-7
- Gregory, Peter. Securing the Vista Environment, O'Reilly Media, 2007. ISBN 0-596-51430-1
- Gregory, Peter; Miller, Lawrence. CISSP for Dummies, Second Edition, John Wiley & Sons, 2007. ISBN 0-470-12426-1
- Gregory, Peter. IT Disaster Recovery Planning for Dummies, John Wiley & Sons, 2007. ISBN 0-470-03973-6
- Gregory, Peter; Simon, Mike. Biometrics for Dummies, John Wiley & Sons, 2008. ISBN 0-470-29288-1
- Gregory, Peter. Data Backup for Dummies, EVault Special Edition, John Wiley & Sons, 2008. ISBN 0-470-40662-5
- Gregory, Peter; Miller, Lawrence. SIP Communications For Dummies, Avaya 2nd Custom Edition, John Wiley & Sons, 2009. ISBN 978-0-470-38114-4
- Gregory, Peter. CISSP Guide to Security Essentials, Thomson Course Technology, 2009. ISBN 1-435-42819-6
- Gregory, Peter. CISA Certified Information Systems Auditor All-in-One Exam Guide, McGraw-Hill Osborne Media, 2009. ISBN 0-071-48755-7
- Gregory, Peter; Miller, Lawrence. CISSP for Dummies, Third Edition, John Wiley & Sons, 2009. ISBN 0-470-53791-4
Gregory has written several articles for Computerworld and Software Magazine including:
- Protect Apps and Data with a Disaster Recovery Plan
- Identify Vulnerabilities with Application Scanning Tools
- Integrity begins within: Security pros lead by example
- Vulnerability Management Ushers an Era of Technical Risk Management
- Security in the software development life cycle
- Tipping sacred cows: Make bold decisions to protect your information
- Lessons learned from the blaster worm
- For an infosecurity career, get the technical basics first
Gregory has been interviewed by trade publications including Information Security Magazine, CIO Magazine, and Computerworld.