The Preliminary Examination is crucial in the UPSC Civil Services Examination as it serves as the first filter for candidates. It consists of objective-type questions designed to assess candidate knowledge in various subjects like current affairs, general studies, and aptitude. Scoring well in the Prelims is essential, as only successful candidates advance to the Mains Examination, which requires deeper analytical skills. Thus, the Prelims determine not just eligibility but significantly influence a candidate's preparation strategy for subsequent stages of the examination.