You have achieved skills and experience – you are a professional!
Most of the time it is so well defined that your full resume is like a manuscript of success. Unfortunately, there are many seeking new pastures. There are many reasons to seek a new home. Competition for professional positions is keen. HR people are often deluged when jobs are advertised with skilled professionals seeking a new opportunity. The average job advertised in any venue will generate thousands of responses. Many HR persons, being deluged with so many qualified applicants, need the most information as concisely as they can get it. It is imperative to get the key words out there in as much space as you can on one page. Like ‘baiting a hook’, when you go fishing. Here you put on enough information about you to get the attention and interest of the perspective employer without telling so much that they need not ask for more. You will need the full resume for an interview but here it is getting them to call you in for an interview. That is the key to a great resume. As in all of these situations, your resume means nothing if it does not give results of getting your foot in the door for an interview.