The first intensive study of birds of Bhutan dates back to 1930's by Frank Ludow. The keen interest of his majesty, the late Druk Glypo Jigme Dorje Wangchuk initiated the next major study of avifauna (1966-1973) through a series of nine surveys conducted by the three of the distinguished ornithologists viz., Dr. Salim Ali, Dr. Biswamoy Biswas and Dr. S. Dillon Ripley. The venture was unique in so much so that scientists from three internationally known organisations came together for the first time for the study. Sadly, the passage of time has taken its toll—two of the three authors (SA, BB) have left us for heavenly abode by the time this book is being published. But their fruits of untiring labour and the abiding love for the beautiful country of Bhutan and the birds can be witnessed in the text of this volume. The authors have now meticulously recorded 516 species of birds from the Kingdom of Bhutan representing nearly 43 percent of the avifauna of Indian region.