This book is not simply a literal translation of the Sanskrit text. It contains even much of the valuable information to be found in the commentary of Nidana by Bijoy Rakshit and Sreekanta Dutta. If the translation conveys an idea of the Hindu system of pathology to those who are unacquainted with Sanskrit and if it thus tends in any way to enhance the respect for those great men whose blood still runs in our veins, I shall think my labour amply rewarded.