The paper presents preliminary empirical evidence on the production of scientific knowledge in Italy, in theoretical sciences (physics), applied sciences (chemistry) and technical sciences (engineer ing and petrology). It elaborates on an original dataset of publications and citations for 2,673 Italian researchers, distributed across 61 universities, covering the years between 1990 and 2004. According to a well-established tradition of studies in the economics of science, the results show that individual distribution is quite asymmetric, with very few researchers accounting for a great amount of scientific output. More interestingly, the paper also shows that there are important differences in terms of asymmetric distribution when the different disciplines, universities and academic positions of the researchers are compared. These differences open the way to interpretation in terms of two main factors. Firstly, the various disciplines can be characterised by specific knowledge bases, learning practices, organisation of scientific labour, and communication norms. Secondly, specific weaknesses in the hiring, incentive and monitoring schemes at discipline and university level can explain different degrees of asymmetry. Both these factors have important implications for a research agenda on the governance of science. Finally, the paper shows that, at the aggregate level, scientific productivity benefit from a concentration of R&D expenditures only to a minor extent, and subj ect to decreasing returns. The effect of externalities stemming from R&D investments is limited. The scope of the concentration of R&D resources can therefore be questioned.