Letters of Sincerity is a study in the traditional Malay art of letter writing. The work is based on the Raffles collection of Malay letters first discovered in Aviemore, Scotland, in November 1970. In this book Ahmat Adam provides a transcription form the original Jawi, into Rumi script of a series of letters sent to Stamford Raffles mostly around 1810 and 1811 by rulers of regional Malay polities. He also provides a translation into English, and supplementary notes, which set the letters in the context of the times, and explain the issues which they raise. In the course of this he additionally povides a detailed guide to the intricacies of Malay-Islamic dating which was in use at that time in the Malay-Indonesian world. His study on this aspect of Malay culture is the first to link Malay dating with Sufism.