Kroll
212-593-1000, www.kroll.com
This full-service international security consulting firm offers corporate preparedness training, intelligence services, and physical protection to executives worldwide.

Elite Agency
212-213-0206
Lou Palumbo, who served 22 years in the C.I.A., heads up the Elite Agency (with offices in New York, Washington, and Los Angeles). His clients range from heads of state to cabinet members of the Chinese government to top executives whom he escorts on international business trips.  

T&M Protection Resources
212-422-0000, www.tandmprotection.com
T&M Protection Resources counts more than a dozen hedge fund managers among its clients. It also supplies bodyguards and armed drivers, and consults on alarm systems and telephone surveillance.

Gavin de Becker
818-506-0426, www.gavindebecker.com
Gavin de Becker, a Los Angeles-based security consulting firm, protects an array of clients, including Sony execs, and provides security consulting services to members of the media, the government, and the academic world.

GSS Security
212-764-5400, www.gss-security.com
John Smaragdakis, of GSS Security in New York, has been in the business for more than 20 years and counts rock stars, business executives, and chic hotels among his high-profile clients.

Gallahad
818-780-1818, www.galahadinc.com
This Sherman Oaks, California, firm provides security for corporate executives and some of the biggest names in the entertainment industry.

Specialist Intelligence and Security Services
011-44-1244-399521, www.siass.co.uk
S.I.A.S.S. is based in Chester, England, but will provide overseas coverage at short notice. The firm is staffed almost exclusively with former army and police personnel.