The purpose is to get you an interview, and the interview is where you close the deal. Just long enough to get you in the door. Focus on your most recent and relevant real-world experience. While it's fine to have a two-page resume, don't list every job you've held. Hiring managers are primarily interested in your last 10 years.
Most companies now store resumes electronically and do keyword searches when positions come up.
To get your name to come up in an applicant search, include the relevant industry keywords. Read descriptions for projects that interest you and use the terms.