An attempt is made to review the literature on the pattern and role of informal communication based on studies carried out worldover. The paper focuses on the following dimensions: (i) characteristics and state of communication, (ii) communication network, (iii) factors influencing communication, and (iv) communication and productivity. The Indian scientists and engineers appear to be dissatisfied with communication opportunities outside R&D laboratory. Most of technical contacts are irregular in nature. It is hard to believe that a large number of professors, readers, and lecturers have not attended any international conference during the past 3 y. Depending upon the performance of individual in channelling information in organisation, the individuals have been classified into three categories: (i) key person, (ii) isolate, and (iii) liaison. Key persons/gatekeepers are a few individuals who attend more symposia/conferences, present more papers, have more inside/outside contacts, and publish more papers than their colleagues. Lack of financial resources, lack of institutional support, opportunity cornered by seniors, promotion and reward system and professional rivalary are important factors coming in the way of communication in the Indian context, while in the European advanced countries important factors are demographic, organizational, interpersonal communication, and social networks.