WHAT IS A STATEMENT OF PURPOSE?
The Statement of Purpose is the single most important part of your application that will tell the admissions committee who you are, what has influenced your career path so far, your professional interests and where you plan to go from here.
 
As the name signifies, the Statement of Purpose is your personal statement about who you are, what has influenced your career path so far, your professional interests and where you plan to go from here. It need not be a bald statement of facts; several successful SoPs address these questions through anecdotes, stories or by describing their hero. But whether your SoP is subtle or to the point, it must be well written to be successful.
This is because the SoP is the only part of your application packet over which you have full control. Your academic and extra-curricular records are in the past. Most people only take one or two shots at the GMAT, GRE or TOEFL, and these scores could be adversely affected by conditions on the test day. It is important to choose recommendation letter writers carefully, but while you hope they give you the best possible recommendation, this is not within your control.

The SoP is your chance to talk directly to the admissions committee. To make yourself stand out from among a multitude of similarly qualified candidates. To convince the committee that you have the spark, the thirst for knowledge that could add value to your class.
Most of us work hard for the standard tests - the GRE, GMAT, TOEFL and others. We attend classes or peruse study aids. We give practice tests and do everything within our power to aim for the highest possible score. Because we know that these test scores, while not a perfect tool, are crucial to our chances of gaining admission and even a scholarship or assistantship.
The SoP or essay, on the other hand, is put off till the last possible moment. It scares us when we look at those oh-so-perfect essay examples in the admissions guidebooks and wonder how we can ever write so well. Or wonder what shining instance we can pick out of our normal, average lives to show that we are unique and remarkable. Or how to pick our way through the minefield of endless Do's and Don'ts. Or, after overcoming all these obstacles, we falter at the seemingly endless revisions, wondering if this latest draft is good enough (If I read that essay once more, I'll scream!). Finally we write something, because time's a-pressing and we have to meet the application deadline. We do our best, juggling the writing process with the last-minute paraphernalia of applying-checking forms for errors and completeness, collating the application packets, making sure transcripts, recommendations, work samples and resumes go in their right envelopes, worrying about transit times. We feel thankful when the essay is over, do a quick scan for obvious mistakes, and send it on its way.
If you do it this way, you are practically throwing away your chances of admission (see the next section,  A good SoP will certainly improve your chances of getting admission to the school of your choice, and even compensate for weaker portions of your application such as less-than-perfect grades. A bad SoP, on the other hand, has the potential to drag down an otherwise strong application.
If you plan correctly, you can give yourself enough time to submit a well-written, thoughtful, polished essay that will boost your chances for admission. Equally important, this is a great opportunity to look inside yourself and be rewarded by a better understanding of who you are.
Writing a reasonably good Statement of Purpose is not an impossible task. It requires care, attention and patience. And enough time for you to be able to write several drafts, show them to people and polish the essay till you get a version you are happy with.
Done right, this will even turn out to be an enjoyable process. And you will be the richer for it.

• Be as honest as you can. Essay evaluators can read between the lines. Do not underestimate them.
• Write the essay yourself. Don't get an expert or your best friend to write for you. The admissions officers can compare your essay style with your grades, test scores, and writing samples from GMAT, GRE or the SAT. If they suspect fraud, the application will be thrown out.
• Get the essay checked. The writing must be your own, but you are allowed to get advice. A parent, friend or counselor can give an opinion on how the essay sounds. You can also get help on grammar, spelling and layout.
• Evaluate rather than narrate. When writing about your experiences it is important to discuss what you have learned. Don't just "tell stories".
• Be logical. Make sure the essay flows well with a proper beginning, middle and end. Each paragraph should follow logically from the previous one.
• Focus. Focus on specific points that only you could have written, and which show your unique personality. Avoid general statements.
• Be positive. Never complain about your school, family or country. If you want to explain why you have bad grades, do so without blaming others.
• Keep the language simple. Avoid quotes because the examiner wants to hear your words. Don't use flowery language.
• Keep it short. Concise writing is always appreciated.
• Pay attention to detail. Use 12 point font. Use a simple font such as Times New Roman. Justify the text (i.e. align to both left and right margins).

 Sample Copy SOP
The following is a shortened sample SOP (with technical details removed.) Expert comments at the end of the paragraphs point out important features.
After one year's work experience as a research technician at [_________], one of the US's leading research institutes, I want to return to academic study and undertake graduate studies in Cell Biology and Molecular Genetics at the University of [_________] stating what you are doing now and what you are applying for is a simple, direct way of starting an SOP.

After graduating with a first class degree from [_________], University of [_________], I felt I should gain some practical experience working in a research environment to gain first-hand knowledge of what the life of a research scientist entails. I have loved every minute of my work: especially the opportunity to participate in cutting-edge projects and discuss ideas with senior biologists. I soon realized that, although I enjoy handling the complex equipment and processing the results, I am not going to be satisfied with carrying out routine procedures under the direction of others. I want to be part of the team that directs the course of the project. My senior colleagues have encouraged my ambition and feel that I have the potential for graduate studies. Notice how the student tries to analyze the reasons for her choices.

My love of biology started in high school. We had a young and enthusiastic teacher, Mrs. [_________], who took us on field trips and visits. She made sure we did as much practical work as was feasible and demonstrated experiments that we hadn't the equipment or time to do ourselves. She also encouraged us to read. I remember the impact reading Maynard Smith's The Theory of Evolution had on me: I wanted to be able to explain such important ideas as clearly as he did. Quite naturally my first thoughts about a future career tended towards teaching I wanted to be another Mrs. [_________].It is good to explain how you became interested in your subject. However, don't go too far back! Notice that a specific example helps create interest.

At undergraduate level, my interests became more focused. Although physiology and ecology came easy to me, it was biochemistry and cell biology that really captured my interest. We were fortunate to have good laboratories and excellent professors. I found that cell biology was an interdisciplinary undertaking: today you need a foundation in chemistry, physics and even IT to be at the forefront in this subject. This interdisciplinary aspect of the subject suits my abilities well. I have always performed well in all science subjects and find it challenging to apply the knowledge to practical problems. For this reason I chose to undertake a project in my final year on the behavior of protein molecules in high energy fields at [_________]. The scientists at [_________] were impressed with my practical skills and were happy to give me a recommendation that led to my present job. Details of courses and projects help to show focus. (This student went on to describe another important college project. She also gave a full description of her current scientific work.)

Many people have asked me why I did not proceed directly to graduate studies after graduating. The answer is that I wanted to make sure that I had chosen the right subject and the right place before embarking on a course of study that would involve many years of my life. The one-year gap has also given me time to work with the local Natural History Society: we take families on Sunday trips to the nearby National Park to help create awareness about environmental issues. I have also been a member and organizer of the [_________] Film Society: we watch and discuss films from all over the world. I am looking forward to furthering my interest in film in the [_________] Film club, at your university, and I also hope to use my passion for teaching in the [_________] Social Outreach program. Explain the reasons for any unusual features of your career (taking a year out, poor performance, etc.). Include social and extracurricular activities to show balance in your life or because they are relevant to the course.

In selecting the University of [_________] I have been influenced by the way your research program addresses biological questions at the levels of molecule, gene and cell. I am particularly looking forward to such courses as Developmental Biology and Bioinformatics. I am also excited to interact with Professors [_________] and [_________] whose work is closest to what I want to pursue for the original research component of the MS degree. I have been corresponding with [_________], a current student, from whom I have learned about the collaborative environment at [_________] where I will interact with talented students, teachers and industry professionals. I believe that I will be able to contribute to and learn from the academically challenging environment at the University of [_________].