(FORTUNE Small Business) – For almost everyone, war is hell. But some entrepreneurs are finding themselves in the awkward position of not only surviving but thriving in these troubled times. Once the owners of obscure and highly specialized firms, these small business owners are offering products and services suddenly in high demand. Now that their niche offerings have become national obsessions, their companies are poised for growth. Of course the challenge, as for any survivor, is to succeed when the war ends. Here are some firms that stand a chance.

--CORA DANIELS

SALIENT STILLS Creator of digital imaging systems Laura Teodosio, CTO and founder Boston www.salientstills.com

WHAT THEY DO: Their patented software, VideoFOCUS, quickly converts video footage into clear high-res photos for media outlets like the New York Times and USA Today. Now Salient, born from Teodosio's graduate work at MIT's Media Lab, is adapting its technology for security firms.

HOW IT'S GROWING: The 11-person staff was called upon by the FBI to comb though hours of grainy Sept. 11 surveillance video from Boston's Logan Airport. Sales for its first year are expected to push close to $2 million, double what it projected. Their technology is now front and center.

ACAMBIS PLC Researcher and manufacturer of vaccines Dr. John Brown, CEO U.S. operations in Cambridge, Mass. www.acambis.com

WHAT THEY DO: This little-known British pharmaceutical company develops vaccines for various diseases, from the West Nile virus to typhoid fever. The 150-person firm, as it turns out, is the only one in the world licensed to make the smallpox vaccine.

HOW IT'S GROWING: The feds are depending on them to ward off disease, shelling out more than $343 million for 54 million doses of the smallpox vaccine. Now talk is under way to stockpile another 300 million doses, enough for every American.

TEMPEST PUBLISHING Publisher of books on bioterrorism Ben Venzke, CEO and founder Alexandria, Va. www.chem-bio.com

WHAT THEY DO: Publisher of intelligence material, including daily terrorism reports for the past 12 years. Its First Responder Chem-Bio Handbook is the bioterror bible of emergency crews. The firm also offers expert advice on bioterrorism to government and law enforcement agencies.

HOW IT'S GROWING: With its books now outselling Harry Potter on Amazon, Tempest sales for the first three weeks after the attack added up to more than 50% of its sales for all of last year. Profits are expected to triple.

INFECTECH Maker of infectious disease diagnosis kits Dr. Mitchell Felder, CEO and founder Sharon, Pa. www.infectech.com

WHAT THEY DO: With 32 patents, Infectech is in the business of fighting deadly infectious diseases. Its gene amplification technology diagnoses specific infections quicker then traditional methods. That helps doctors prescribe the perfect antibiotic cocktail for treatment.

HOW IT'S GROWING: After wallowing in anonymity for years (sales last year were just $50,000), attention from Washington health officials has the seven-person operation working overtime and braced for rapid growth.

TASER INTERNATIONAL Developer of nonlethal weapons Rick Smith, CEO and founder Scottsdale, Ariz. www.taser.com

WHAT THEY DO: Devastated by a road-rage incident that left two of his friends dead, Smith started this stun-gun manufacturer so that people could defend themselves. Lack of consumer interest since its inception has prompted Taser to tailor its business to police departments.

HOW IT'S GROWING: The long-awaited public interest is finally here. Annual sales are expected to double to $7 million. If taser guns become standard on marshaled flights (the company is currently in discussions with the FAA), revenues could soar.