The history and directory of the IT security industry.
Security Yearbook 2025 is the definitive record of cybersecurity — the story of how the industry was built, plus a complete directory of 4,000+ vendors. Richard Stiennon's annual reference, trusted by investors, founders, and security leaders worldwide.
ISBN 978-1-394-33486-5 · A History and Directory of the IT Security Industry
Inside the book
A history and a directory, in one volume
Part definitive narrative, part exhaustive reference — Security Yearbook 2025 is the book security professionals, investors, and analysts return to every year.
The history
How the cybersecurity industry was built — told decade by decade, from the first antivirus vendors to today's 4,000-strong market. The narrative no other reference puts in one place.
The directory
Profiles of more than 4,000 cybersecurity vendors across 18 categories — the most complete map of the industry available in print, updated for the 2025 edition.
The analysis
Funding, M&A, headcount trends, and the forces shaping where security goes next — Richard Stiennon's analyst-grade read on the market, distilled into one volume.
The analyst behind the data
“The cybersecurity industry moves faster than any analyst can track by hand. Our goal with IT-Harvest is to give decision-makers a living, breathing view of the entire market — updated as quickly as the companies themselves evolve.”
Richard has tracked the cybersecurity industry for over two decades — as VP of Research at Gartner, CMO at Fortinet, and the author of 14+ books, including the annual Security Yearbook. IT-Harvest puts that career of research into a platform anyone can use.
- Former VP of Research, Gartner
- Former CMO, Fortinet
- Author of the Security Yearbook series
- MA, War in the Modern World — King's College London
Get your copy of Security Yearbook 2025
Order the Sixth Edition on Amazon. Want the directory continuously updated and searchable? Explore the live data behind the book at IT-Harvest.