Ira Lifland is a special kind of private eye. He speaks in a smooth, cultured voice nothing like the staccato toughness of movie characters like Sam Spade. And instead of tracking down unfaithful spouses or small-time crooks, the chief operations officer of Los Angeles-based Sultan & Co. focuses on bigger game: high-priced executives whose bad habits or financial debts could undermine their performance in a key job.

Mr. Lifland points out that standard background checks now go beyond just ringing up a couple of personal references, especially for technical workers who often have access to strategic company information. Employers "cast as wide a net as possible, then follow up all the leads they can," Mr. Lifland warns. He advises job hunters to do the same.

Unfortunately, many technical professionals make employment decisions solely on the information they glean from job interviews and perhaps what they read on a prospective employer's web site. In short, they're making long-term career decisions using only information over which the employers have a great deal of control. Such blind faith can be especially dangerous for technology workers, who often find themselves choosing between a company that has a clear information-technology vision and one that's about to be left in the technological dust. The result: Within months or weeks you may find yourself in a difficult work environment after letting a better opportunity slip away.

Fortunately, there's help. Employment experts and business intelligence super sleuths like Mr. Lifland say that all it takes is a little legwork and resourcefulness to get inside information on a company -- even private ones.

The first step is to make sure you get the easy data. Public companies are required by law to publish recent earnings reports and to acknowledge pending lawsuits, among other juicy information that can help you gauge their potential for profitability. Web sites like Companysleuth.com provide this information in an easy-to-search format. Just type in a company's stock ticker ID and Companysleuth presents recent news reports from print and TV outlets, trademark and patent filings, SEC documents, stock quotes and analyst ratings.

Important as this information is, it won't tell you much about the company's work culture or how satisfied its employees are to work there. Companysleuth also doesn't provide inside information about private firms.

Vault.com can help in both of these areas. "In an ideal world, we'd all have 12 cousins we could contact at Microsoft if we were considering taking a job there," says Mark Oldman, a company cofounder. Vault.com can't provide additional relatives, but the four-year-old site does have a staff of 20 researchers who regularly interview and survey about 3,000 companies across the U.S. Among the key data points that Vault.com offers free to visitors are salary levels, promotion policies, perks and attitudes about flextime. The site also runs an "electronic water cooler," an online chat area where you can request insights about a particular private or public company from any current or former employees who are online. Browse through messageboards dedicated to "High Tech" or "Internet" and you'll find critiques that range from glowing to crushing.

Once you're done with your Net research, it's time to visit your prospective employer. If you're arriving for an interview, get there early. Karl Shinn, senior managing partner for the career-counseling company OI Partners Inc. of Fort Lauderdale, Fla., tells clients to hang out in the parking lot to pick up clues about a company. "Act like a sponge collecting information," he says. Notice how employees dress -- you'll get a sense of how formal or informal the work environment is to help you gauge how you might fit in. At the same time, seeing how people interact -- do they greet each other or walk to the door with their heads hanging -- reveals a lot about how enjoyable the place is. If possible, go both early and late in the day to try to determine the time commitments the company places on its employees. Mr. Shinn also likes to informally chat with landscapers, guards and receptionists to gauge their degree of satisfaction and long-term interest in the company.

Mr. Lifland likes to catch someone standing in the lobby or walking out the door to see if they'd accept a phone call after business hours. "People don't know you and many may not cooperate. But others will, and from them you'll learn a lot about whether this is a great place to work or whether the managers are tyrants who will keep you there every night until 10," he says.

Another sleuthing technique Mr. Lifland uses is to search newspaper archives for stories that mention current or former employees he can track down. Also, he looks for stories about any pending litigation and calls the opposing lawyers to get their take on the company.

Once you've gathered your intelligence, it's time to explore one more area: your heart. "Finding a dream job starts with some soul-searching," says Mr. Oldman of Vault.com. "You need to know what kind of environment you're really looking for. It's not reasonable to crave a laidback environment, and then go looking for work at an investment bank."