New Delhi, March 14: As the embattled Sahara chief Subrata Roy completes two years in prison, there is something he can cheer about. Roy’s book "Life Mantras", which hit the stands last month, has been rated a bestseller in the non-fiction category by Nielsen Bookscan, a data provider for the publishing industry. "Life Mantras", brought out by Rupa Publications, is the first book in the trilogy titled "Thoughts from Tihar" by Roy, who is behind bars for failing to pay Rs.24,000 crore to Sahara’s investors. The book topped the list during the week of February 14-20, pushing the popular Manorama Yearbook 2016 into second slot, says Vikrant Mathur, director, Nielsen Bookscan - India and Asia Pacific Region. "Mrs Funnybones" by Twinkle Khanna was in the third place during the week. It has since slipped to the third slot, according to Mathur. “Our methodology of collecting retail sales on weekly basis is adopted across the globe. Retailers in the panel have EPOS (Electronic Point of Sales System) facility and the data is being sent to Nielsen,. The output data is the result of aggregation of the retailer’s sales data and provided to the participating retailer and subscribing publishers,” explains Mathur, adding that they collect data from online and offline booksellers. The survey, done from every Sunday to Saturday, does not cover the entire market. The bestseller of the week is decided by the number of copies sold across the board by retail chains. Nielsen, however, declined to quote the figures which made "Life Mantras", a topper. Some of the booksellers included in the survey are Bookadda, Crosswords, Connexion, DC Books, Flipkart, Indiatimes, Infibeam, Landmark, Rediff, TV18 Homeshopping, WH Smith India, ebay, Reliance Timeout, and Snapdeal. Besides India, Nielsen Bookscan also operates in Britain, Ireland, Australia, US, South Africa, New Zealand, Italy, Brazil and Spain. Calling his imprisonment a “rude shock”, Roy writes in his book, “I, like any other human in confinement, could not contain my thoughts and at times felt an emotional outrage, ‘why me?’, ‘what have I done wrong to deserve this?’” Describing life in jail as painful and lonely, Roy says that he has managed to lead a totally tension-free life. While the second book in the trilogy is "Think with Me - How to make our country ideal", the last one is titled "Reflections from Tihar - A book on Tihar Jail". Both the books are being published by Rupa and are expected to be released soon.