Thematics Publications: SDI is a type of current awareness service meant to keep the user abreast with the latest developments in the field of his interest. It is a personalized service meant for the individual or a group of users having identical information needs. It is a quick service which provides the pinpointed and exhaustive information to the users. SDI involves the screening of the document and selecting the information according to the specific information needs of each user or group of users (homogeneous). The main objective is to keep the user well-informed and up-to-date in his area of interest. Definition of Selective Dissemination of Information: Selective Dissemination of Information (SDI) is defined as the system in which selectively and automatically compiled information about new documents is disseminated to researchers, scientists and others who need these documents/information or supplying each user or group of users with a reference of documents or abstracts relating to their predefined areas of interest. It involves notifying the material that matches the interests of the client. Selective Dissemination of Information was a concept first described by H.P. Luhn for the scientist /engineers of IBM. According to him, “The Selected Dissemination of Information is the service within an organization which concerns itself with the channeling of new items of information, from whatever sources, to those points within the organization where the probability of usefulness in connection with current work or interest in high. On the other hand, the service endeavors to withhold such information from the points where the probability is low.” Judith Holt Connor defines SDI service as a manual and automated service which attempts for a personal service (CAS) selecting for each individual that are relevant to him. “It is activity of supplying a clientele on a regular basis with requested, specific type of information the emphasis is on the specific.” – Edmon Wearing. Cheracteristics of SDI: The following are the characteristics of SDI service: It is a computerised assisted service. SDI is concerned with current published information. The source of current information may be available both within the organization and outside it. The new / current information should be disseminated to the users such as researchers, scientists, managers, etc. within the organization. The channeling or directing of this information depends upon the nature of this interest. One of the important things in SDI service is that only current and selective information which is highly relevant to the user’s interest is to be selected by the computer for dissemination. Objectives of SDI: Some of the objectives of selective dissemination of information (SDI) services are as follows: To provide current information on a predefined area of interest. To receive, scan and provide the literature / information to the right users at the right time. All the current information which is relevant to the interest of the user must be brought to the notice of the user (notification). All the relevant information which is published elsewhere in the world (in English or other languages) should be located through various sources. To achieve current requirements through the scan of current material such as journals, current awareness bulletins and other important resources. To save the time of the user. No irrelevant documents should be brought to the notice of the user. Only the selective and relevant documents should be brought to the notice of the user.