The mountain flora of Java constitutes a unique natural heritage of Indonesia and indeed of the whole world. The most informative and most beautifully illustrated book ever written on this rich resource is doubtlessly "The Mountain Flora of Java" by C.G.G.J. van Steenis, with unsurpassed paintings of 456 flowering plant species by Amir Hamzah and Moehamad Toha. The first edition from 1972 was sold out fairly soon. Brill is therefore proud to publish this edition of this seminal work at this point in time. There are three very good reasons to reprint the "Mountain Flora" both in English and in the Indonesian language. First of all there is the importance of this flora for biodiversity conservation and sustainable use of the vulnerable montane ecosystems of Java. Secondly, the unique style and quality of the 456 plant portraits by Amir Hamzah and Moehamad Toha. Thirdly there is the science, explaining and interpreting the rich botanical diversity in the mountains of Java. Although written over 34 years ago Van Steenis' approach to the study of botany can still serve as an example and inspiration for young botanists, conservationists and policy makers.