During my internet travels I bumped into a topic revealing an art of divination that analyzes the lines in the forehead. I found it fascinating and after some sleuthing, I prepared the info presented here. In the meantime, I'll be busy sitting in front of a mirror analyzing my own lines.

METOPOSCOPY is the reading of character using the lines if the forehead.

Metaposcopy is thought to have originated with the ancient Chinese and even in modern times, various methods of face reading are still in use by a number of Asian cultures. From the East, the art of Metaposcopy probably traveled to Europe where it was taken up by the ancient Greeks. In fact the great philosopher Aristotle was a firm believer in Metaposcopy and its power to correctly analyze the human character while Hippocrates, the highly revered scholar-physician, went so far as to think of Metaposcopy as a legitimate science for diagnosing the traits of future diseases.

The practice of Metaposcopy was developed by the 16th century astrologer and physician Jerome Cardan. He was an Italian Renaissance mathematician, physician, astrologer and gambler. In fact his habit of compulsive gambling led him to contribute to the theory of probability in a major way, making him one of the founders in the field. As regards to Metaposcopy Cardan wrote two encyclopedias of natural science which contained a wide variety of inventions, facts, superstitions and occult practices among which was included his theories on interpreting the character and destiny of person through a study of the lines on his/her forehead.*

According to Samudrik shashtra there are seven lines present on human forehead.

1. The line of mysticism (Saturn)
This is the top most line on your forehead. Very few people have this line and among those who have it, the line is incomplete. This line is mostly found in people who are good with analysis and have a scientific bend of mind. Mostly these people have an exceptional ability to foresee things. They can critically analyze any theory. This makes them good with research. The ones with line of mysticism are very hard working. They have huge passion to find the unknown. They can spend hours in the labs or in the study. They will not rest until they have found all the answers to the questions that they have. This makes them loners as they like to spend more time on research and less time on socializing. They might not be a good option for marriage or for a relationship. Some experts do believe that this line of mysticism is a sign of extra intelligence.  This is perhaps not needed. If the talent of these people are not channelized properly then the person might become a criminal. They can be very smart and can crack any code. These people are also professional hackers at times. If you have a child with this line then you must ensure that you understand the talents of the kid and make them work towards the same. The ones with a line of mysticism will mostly be very sharp. They can be good magicians as they will normally have a brain that has an edge over others. Many top magicians in the world have this line on their forehead. Any job that requires a different line of thinking can be easily taken up by these people.**

2. The line of wisdom (Jupiter)
This is the second line from the top. If you have this line, you are a seeker of knowledge and truth. You are just in your assessments, have a balanced outlook and good discernment. Self-confidence comes easy to you. If the line is deep and smooth, you may be a teacher of higher knowledge or make a good writer and can easily hold a high position. If the line has many branches and/or tributaries, you could be foolish, deceptive and lacking in ambition.

3. The line of courage (Mars)
Right beneath the line of wisdom is the line of courage. The physicality of the line indicates your level of ability to face fear. A straight line of courage means you can face anything and no matter how harsh the situation you will come out on top because you are a good strategist. A crooked line indicates aggression that can take on very negative and violent forms.

4. The line of intelligence (Sun)
This line reflects level of intelligence. If it is well-formed and extended, you are logical, rational, observant and find it difficult to deal with that which is irrational. You have a good understanding of human nature and may be adept at manipulating others. If the line is small, you might be a magpie who talks too much and may fool or dupe people at times.

5. The line of love (Venus)
If you have a solid well-formed line you are attractive to others, popular and exude a love of life. You need peace, and equity, hate disorder and like material things. You are social and enjoy forming lasting bonds with others. A crooked line might mean you are a bit lusty.

6. The line of success (Mercury)
This line is located above the right eye and generally, it is not bigger than the eyebrow. A strong line indicates success because you have good foresight, excellent mental faculties and good carry through. Your personality shines and people tend to like you because of your sparkle. If the line is crooked you may be a bit of a scalawag and possibly infamous.

7. The line of imagination (Moon)
This line is located above your left eye. If it is straight and well-formed you have an amazing imagination. Realm walking is natural to you. You know what you want, are clear in your ideas and know how to express yourself with marvelous articulation. Creativity and beauty are your bi-words. If the line is crooked, you may be too conventional or a stuffed shirt and may have trouble expressing yourself.

Other particulars:

• Nicely formed Saturn line indicates good vision, and thinking mind .Any line going upward from Saturn line is not good sign such person will face struggle in life.

• Downward tringle on Saturn line indicates that person will change his religion or can marry in inter-caste.
• If Saturn line is long and Jupiter line is wavy then such person would be dominated by his spouse.
• If half-moon present is present on Saturn and Jupiter line and moon and sun line are joined together then person will very fortunate.
• If trident (trishool) mark is present between sun and Jupiter line such person will acquire divine power.
• If any line originated from mars line and cuts sun line then person will face financial problem.
• If Saturn line is long and mars line is wavy then person will acquire high status.
• Nicely formed Saturn, Jupiter, Mars lines indicate native will very fortunate.
• If there are many small broken lines present on forehead then such a person will face many problems.
• Four nicely formed line indicate good character and intelligence.
• If any branch of mars line is going toward sun line this indicate promotion in life
• If Jupiter line is divided into two parts then this indicate financially instability
• Branches in Jupiter line indicates such person will be lair.
• Tilted Saturn line indicates bad character 
• Wavy mars line makes one criminal.
• Small sun line and long Venus line will indicate such person will be cleaver and fortunate.
• If there is trident present between eyebrows then such person may lose one of his body part.
• If Saturn and Jupiter lines are wavy then such person will be selfish and liar.
• If Mars line is short and sun line is long then such person will be rich and intelligent and give happiness to others.
• If there is only one bow shape line present on forehead then such person will keep on travelling and he may get involved in bad deeds.
• Many branch lines from Venus line to moon line shows bad financial condition.***

Resources:

* http://www.futurescopes.com/metoposcopy/8592/metoposcopy-reading-lines-forehead-see-future

** http://www.metaphysics-knowledge.com/miscellaneous/lines-on-forehead-the-line-of-mysticism.html/

*** http://ashishastrologer.blogspot.com/2013/08/significance-of-forehead-lines.html