LoJack's Stronger Signal

William R. Reagan was never a cop, but as town selectman in Medfield, Mass., in the late 1970s, he carried a badge and held the title of police commissioner. One night in 1977 he pulled someone over who turned out to be a paroled convict. A thought nagged at Reagan: "He could have had a pistol on his lap and blown me away." That episode, Reagan says, spurred him to develop a radio tracking device designed to help police recover stolen cars and reduce the number of dangerous stops. He called his invention LoJack -- "it's the antithesis of 'hijack."'

Almost 30 years later, LoJack Corp. (LOJN ) has become an unlikely growth story. Under new management (Reagan cashed out by the late 1980s), the Westwood (Mass.) company has spent the past three years fine-tuning its sales approach. Over that period, LoJack's profits have soared an average 68% a year on sales that have grown 19% annually -- good enough to be No. 42 on BusinessWeek's Hot Growth ranking of small companies. Reagan and a handful of investors took LoJack public two decades ago, but lately investors have taken notice: Its share price has risen from $4 in 2002 to around $23 in 2005.