It's the question I am most often asked by readers. How do you spot a jerk before you start dating him (or her?)

He always "forgets his wallet" and sticks your friends with the dinner tab. She screeches at the shampoo boy for using the ylang ylang essence instead of lavender, and it's obvious only to them that there's not another competent driver within a 50-mile radius.

You're offended, you're humiliated, you're walking on eggshells: somehow you've ended up dating a jerk.

There are the classic signs, of course. Conventional wisdom suggests you look at the way someone treats people they perceive as "don't matter" people -- a waitress, the ice cream store guy, the woman who cleans his apartment. If he's snotty to wait staff, condescending to strangers, mean to people he's not trying to impress, it's only a matter of time before you're on the receiving end of all that irritation and condescension. That's right: today his steak is overcooked and the only acceptable solution is the waitress's public humiliation and immediate dismissal. Tomorrow, you're the incompetent, disappointing moron.

John Van Epp, author of a new book called How to Avoid Marrying A Jerk

says, "Jerks have no gender, the only difference is the package they come in."

How Do You Spot a Jerk?

Other than a wake of tearful customer service managers and shaky restaurant staff, how can you spot a jerk? According to Van Epp, there are three tell-tale signs:

1. A Habit of Breaking Boundaries

Van Epp says, "These include players and [personal] space-invaders (What is mine is mine, and what is yours is mine.)" This immediately struck me, since I spent a good part of last Saturday night watching a big drunk guy in an orange shirt pawing a succession of strange women on the dance floor like a grizzly in heat. Jerk? I think so.

2. The Utter Inability to See Anything from Anyone Else's Perspective

The other guy was rude, the donut guy was an incompetent, the Democrats or Republicans (or Liberals or Conservatives, take your pick) are ruining the world. It's often hard to see from someone else's perspective, but a non-jerk will try. Van Epp says, "In time, you will realize that you are invisible to your partner."

3. Dangerous Lack of Emotional Controls and Balance

According to Van Epp, "Emotionally unstable people live on the extreme right or the extreme left of center. The people on the left are flat-liners, with no emotional pulse. At first they appear easygoing, but later you realize that they are cold and detached. On the other side are the overreacting types who are the life of the party, known for their enthusiastic and entertaining personalities, addicted to captivating and fast-paced romances that mask their deeper problems under a shroud of attentiveness and passion. With time and exposure, their dark side emerges."

Are You A Jerk-Magnet?

You might be. Van Epp says, "Good hearted people have the greatest risk for staying in a relationship with a jerk because good-hearted people so quickly forgive, overlook problems, minimize shortcomings and give second chances."

Of course, some of these traits are necessary to keep a relationship on track. But if you find that you're on the giving end of forgiveness more often that the receiving end, you might be setting yourself up for jerk after jerk after jerk.

Another common mistake is love (and relationship) at first sight. "One of the most common ways you become set up to get involved with a jerk is by accelerating the pace of your relationship." Oprah recently had several women on her show who had all married or been engaged to the same guy, frequently at the same time. With nearly all of them, Mr. Romantic had proposed within just a few short weeks or months of dating them, and would end a blowout with one by proposing to another.

Van Epp says, "Only after some time do narcissists reveal their extreme demands -- a kind of 'buy now, pay later arrangement.'

"Once one disappointment blemishes the relationship, the narcissist can never retrieve the fantasy feeling of true love."

Lisa Earle McLeod, author of Forget Perfect says, "Jerkiness is related to narcissism. A jerk usually has a long history of failed relationships, and they'll always tell you why it was the other person's fault. The relationship gets really serious really fast, they get infatuated, but the second the jerk finds out that you're not perfect and you no longer see them as perfect, they become demanding and critical."

The Road to Jerkville

Obviously, none of us would go for a second date if a jerk showed his (or her) true colors before the appetizers arrived. But some jerks can be quite charming in the beginning.

And sure, we all act like jerks once in a while. We scream in traffic, we lose it when the carpet cleaners ruin our drapes by tying them in a knot with their grimy hands, we freak out when our partner says something that strikes a nerve. But, according to Van Epp, "The most fundamental, identifying feature of true jerks is their persistent resistance to ever changing their core jerk qualities."

Jerks aren't usually jerky in the beginning of a relationship. But a fast-paced, head-over-heels romance can be enough to cloud anyone's judgment.

Van Epp says, "Resolving your emotional necessities is the first step to avoid a marriage to a jerk. It is also an indispensable step to avoid becoming the jerk."

According to Van Epp, people who always end up with jerks, "consistently lack a 'head' knowledge of what to look for in a perspective partner"

In this day and age, we choose our partners on your own whereas in the past, your family and friends were all involved in the process. So even if you were all gaga and starry-eyed, Great Aunt Leona was still keeping a clear head and an eye on your future.

And McLeod says, "The old saying goes, 'Think with your heart, not your head,' but before you go moving in together or blowing two months salary on a ring or worse, wasting seven years of your life with a loser, try ignoring your heart and taking your brain out for a spin."

Dr. Molly Barrow, author of Matchlines: A Revolutionary New Way of Looking at Relationships and Making the Right Choices in Love says, "Listen to your girlfriends! Better yet, listen your mom! Another source to turn to are your kids. Your children are very sensitive, and although they will not always like all the new men (or women) in your life, they will really hate someone who is a jerk."

According to Van Epp, there are five universal human bonding dynamics: Know, trust, rely, commit and sex. He suggests that "you should never go farther in one bonding dynamic than you have gone in the previous."

In other words, don't go swinging naked from a trapeze on the third date if the rest of the categories are still stuck in "Hi, nice to meet you." And don't fall in love with someone you barely know. Balance in all five categories is key.

Welcome to Jerks Anonymous. Can a Jerk be Reformed?

According to Van Epp, usually not. He says, "No matter how many times they have been confronted by you or others, they still persist in their hurtful pattern. If it is possible to reform a jerk, it will almost always require a major life crisis or life-transforming event, but the longer the track record, the lower the likelihood for improvement."

So, unless he gets struck by lightning or abducted by aliens, the jerk is probably here to stay.

Dating Expert Lisa Daily is the author of Stop Getting Dumped!