In the present book Chapter - I is an introductory one. It contains the general introduction about the problem of distributed lag models. Chapter - II deals with the specification of the distributed lag models through expectations models.Chapter - III describes the estimation methods for different finite distributed lag models existing in the literature.Chapter - IV gives the details about the various infinite distributed lag models existing in the literature along with the estimation of their parameters.Chapter - V develops a new estimation procedure for a finite distributed lag model by using Bernstein polynomial approximation to a function on which the lag weights are assumed to lie. Chapter - VI depicts the conclusions Several relevant articles regarding the distributed lag models have been presented under the title 'BIBLIOGRAPHY'.