After her fine book on Hyderabadi food, Pratibha Karan has now published Biryani, an exquisite book that focuses entirely on biryanis and pulaos. The choice could not have been more apposite for these delicacies are much sought after in every nook and cranny of the sub-continent except in eastern India. But even here, the Kolkata biryani and the Kampuri biryani of Assam are a superb treat. Among the many qualities of the book, one deserves to be mentioned right away. For as long as one can remember, food lovers have wanted to understand the differences between a biryani and a pulao. In his classic Lucknow: The Last Phase of an Oriental Culture, Abdul Halim Sharar observed that for the uninitiated the two are much the same. The only difference is that a biryani is spicier than a pulao. And he went on to tartly add that, "a biryani is an ill-conceived meal in comparison with a really good pulao and for that reason the latter was more popular in Lucknow". Pratibha Karan offers a down-to-earth explanation. Par-boiled rice is used in a biryani;in a pulao, the rice is cooked in just enough water, or in a lamb or chicken broth. Spices dominate the flavour of a biryani while they are underplayed in a pulao. The biryani comes layered - rice alternating with lamb or chicken in two or more layers - whereas all ingredients are cooked together with the rice in a pulao. What is common to both of them, however, is the use of a cooking technique called dum. The lid on the pot is sealed with dough, or hot coals are placed under the pot and on the lid, to ensure that the aroma and the flavours remain intact. When I was growing up in Pune, a Muslim neighbour, who was a professional cook, would place a cloth between the pot and the lid before closing them tight with dough. It took me years to find out why. In the mid-1990 s, when I began to develop an interest in the history of food, I came across references to this technique in the works of experts on Middle Eastern culinary traditions like Maxim Rodinson, Charles Perry and Claudia Roden. They explained that the word pilaf, or pulau, means a way of cooking rice in such a way that each grain remains separate from the other. The rice is soaked, often overnight, to get rid of the starch. It is then cooked in an open pot and frequently stirred until it is almost done. A cloth is placed on the pot before the lid is put on it to protect the rice from the drops of steam that might otherwise spoil the fluffiness of each separate grain. Two 13th century Arabic cookbooks describe the technique in detail though here the dish itself is called ruzz mufafal, which translates as 'peppered rice'. But it uses no pepper at all. The allusion is to the grains of rice which, when cooked, resemble peppercorns. The word for the dish was coined by the Persians in medieval times. It was known as pulow, now pronounced as 'polo'. The Turks called it pilav, the Russians, plov, and the Central Asians, palaw. Traders, adventurers and invaders from Arabia, Turkey, Persia and Central Asia introduced the pulao in the sub-continent. Mughal emperors refined it. Humayun, who spent a good part of his life in Persia, was mainly responsible for exposing the Indian palate to Persia's sweet-and-sour flavours and for the extensive use of nuts, cream and saffron in many dishes. Emperor Jahangir's wife, Noor, learnt from foreign travellers how to use colour to enhance the visual appeal of food. But it was in Emperor Akbar's time that Mughal cookery, imbibing local aromas and flavours, especially of Rajput provenance, scaled the heights of versatility and sophistication. The hundred recipes in Pratibha Karan's book attest to the Indian flair for adapting dishes introduced from the Middle East and Central Asia to suit Indian tastes. To name anyone of them would be to do injustice to the others. Each one is distinctive, subtle, sophisticated. But one mystery remains unresolved: we know the etymological origin of the pulao. But where does the word biryani come from?