CONTENTS: Foreword-Anand Bardhan, Foreword-R D Gaur, Foreword-W S Lakra, Foreword -Dr Rajendra Dobhal, Preface, About the Atlas, INTRODUCTION: Diatoms and their Ecological Importance, Purpose of the Atlas, HABITATS IN THE DRAINAGES OF THE INDIAN HIMALAYAN REGION: The Himalaya, The Dehradun Valley, General features of the Dehradun Valley, Description of sampling locations, Physiography of sampling locations Vis-A-Vis Habitats, ATLAS OF HIMALAYAN DIATOMS: PLATES 1-37: Centric Diatoms, Pennate Araphid, Eunotiold and Monoraphid, Monoraphid, Biraphid, DISTRIBUTION OF DIATOMS FLORA ACROSS INLAND WATERS OF INDIA, Bibliography, Appendices, General information on physico-chemical characteristics, diatom density and species diversity indices of Dehradun Valley, Species Accumulation Rate in the Valley.