The first benefit of having an agent is editorial. Most agents will
guide you through revisions to make sure your manuscript is the best it
can be. Editors know that agents only take on work that they think is
excellent, so they read agented work faster. The agent knows who to send
your work to, and when. Sometimes the agent will send a manuscript to
more than one editor, and in some cases, only to one editor. The agent
knows what is best for each manuscript. Your agent will also negotiate
your contract for you and make sure that all the clauses are in your
best interest. And your agent will keep an eye open for possible
subrights sales—if the agent has kept those rights for you—after you
have signed the contract. An agent will be interested in building your
career beyond one book, so she may even suggest other books for you to
write.