This manuscript containing fine paintings of cats is in the format of a samut khoi (Thai folding book) with 12 folios, which open from top to bottom. It was produced in the 19th century in central Thailand. Folding books were usually made from the bark of mulberry trees; minerals, plant liquids, and occasionally materials imported from China and Europe were used as paints. Sometimes the paper was blackened with lampblack or lacquer to make the paper stronger and more resistant to damage by insects or humidity. Such books were mainly used for the production of non-religious manuscripts in central Thailand. The rather short captions give descriptions of the features of different types of cats that were known in Siam (present-day Thailand). For each type of cat there is also a note explaining what effect keeping this cat might have on its owner. Unfortunately, as is often the case with Thai manuscripts, no author name, illustrator name, or date is given in the manuscript. In 19th century Siam, there was a tradition of producing treatises on animals that played important roles at the royal court and in monasteries. Among such were, first of all, elephants, particularly albinos, but also horses and cats. The breeding of the famous Siamese cats was originally reserved for the royal family. Certain cats also were believed to be the “keepers” of Buddhist temples, which resulted in these cats being closely guarded and highly revered. There was a strong belief that certain types of cats could bring good luck, prosperity, or health to the owner, whereas other types of cats were regarded as unlucky and to be avoided. For example, a white cat with nine black spots, auspicious green eyes, and a strong and beautiful voice was regarded as a lucky cat. It was said that however poor the owner of this cat might be, he or she would become a respected person and gain a high social status. The manuscript was brought to the British Library in February 2011 by the wife of an elderly manuscripts collector in the United Kingdom. The manuscript could easily be identified as a treatise on cats, similar to a manuscript already in the library’s Thai collections (Or 16008). The significant difference between the two manuscripts is that the illustrations in this item are watercolor paintings on cream-colored paper, whereas the other manuscript contains drawings in white chalk on blackened paper.