This paper considers the concept of interest and especially interest in science. An empirical study, which is based on theoretical considerations of the concept of interest and its relation to motivation and engagement, is described. The empirical study consists of life history interviews with six individuals, who all are engaged in nature and/or science as part of their job or hobby. The results from these interviews point to the need of a broader understanding of interest than is generally accepted in the traditional psychological sense. It is suggested that the notion of interest should be viewed partly as interest based on attitude and partly as interest based on action. The results also point to the need of clarifying the meaning of interest in science as it covers both interest in nature and the being in nature, interest in science as a school subject, and interest in science itself.