Can you spot a player? Here are tip-offs from author Neil Strauss, who spent two years spying on pick-up artists for his book The Game.

He's just playing games if ...

1. He gives you guilt trips. Says Strauss, "One guy I knew told a girl who was hesitant to go home with him, 'I thought you said you were spontaneous and a free spirit.'"

2. He's got a gimmick. Pick-up pros call this "peacocking" -- doing something outrageous to pull a woman, any woman, in. (One guy wore seven-inch platform shoes.)

3. He gives backhanded compliments, like "You kinda have man hands. But you're cute." (Actual line!). It's an attempt to make you feel insecure so you'll want to win a guy's approval -- in bed.

4. You're not sure how he feels. If you're always asking your friends whether they think a guy likes you or not, the answer is no. Don't ignore your intuition. As Strauss says, "It's your best defense against a player."

He's serious if...

1. He's happy to hand over his favorite book/CD/sweatshirt if you ask to borrow it. "A clear sign he's fully planning on seeing it -- and you -- again," says Strauss.

2. He's brought you to his favorite bar. Strauss says: "If a guy's integrating you into his daily life, then he's looking to make you a permanent part of it."

3. He returns your calls quickly. Players thrive by messing with your mind -- one guy told Strauss he let a girl leave him 12 messages before calling her back.

4. He goes to your nephew's fifth birthday party with you. "A man who sees you as just a fling is usually going to avoid situations where there's zero chance of having sex with you."

1. He Texts You Between Noon and 5 p.m. This means you're his priority. He's waited long enough not to look desperate, yet he's leaving time for you two to make solid plans.

2. He Schmoozes With Your Pals. Despite what he may say, he's seen Sex and the City enough to know how influential friends are.

3. He Takes You Out During the Day. Someone who invites you to lunch legitimately wants to get to know you. Bonus points if he's willing to come to your neighborhood.

4. He E-mails You. If he sends a message during a work day that might mean he was stressed out and using you as a pleasant escape.