THE LEGAL RELATIONSHIP BETWEEN WRITER AND AGENT
Long before you whip the last page of your novel out of your typewriter (or your printer), you'll begin to plan your search for an appropriate publisher. You might scout out suitable publishing houses and submit your work directly. Many people have done so successfully, but your work is likely to sit on the slush pile until an overworked editorial assistant finally samples a few pages.
One way to improve the odds is to ask around until you find someone who knows your target publishing houses and who is willing to introduce you to an editor. This networking technique can be a very effective way to get a good book idea to an interested editor.
Many writers decide against representing themselves, concluding that it makes more sense to engage an agent to try to sell their work. Obviously, writers who abhor selling things, and all the business negotiations and interactions that commonly accompany sales, will be particularly interested in arranging for help with this part of their literary lives. Others who are more comfortable with business decisions may feel differently, asking what, exactly, an agent can do for them that they can't do for themselves.
There is, of course, no easy answer to whether you need an agent. Your decision should very properly be influenced by all sorts of subjective factors peculiar to your situation. However, we can give you some general insights about what a good agent can do for you.