According to Theo Haiman, staffing involves placing, developing, and managing employees to accomplish work through others' efforts. It is a long-term process that requires investment and involves interrelated functions like planning, recruitment, selection, training, performance reviews, promotions, and compensation, using both internal and external sources. When done effectively, staffing provides benefits like quick learning, higher productivity, cost-effectiveness, better management, employee benefits, less supervision needed, and higher morale.