This article introduces the presence construct offering in the same time a review of presence determinants. Highlighting the uneven interest manifested in this research area, interest which favours particularly technological factors, it advocates a shift of attention which would motivate studies focusing primarily on human factors. The article continues by outlining the methods and instruments developed for assessing presence, with an emphasis on the challenges and difficulties of measuring presence. Given its significance, the relationship between presence and task performance is also discussed.