David was the longtime head of the Geocryology Laboratory in Pushchino, Russia. David's primary scientific legacy is that he demonstrated to a skeptical sci- ence community that the Siberian permafrost contained viable microorganisms that had beenimmobilized in the ice-cemented ground for up to 5 million years. This was an important discovery and motivated themicrobiological study of putative 25-mil- lion-year-old ice in Antarctica; it spurred those of us interested in Mars to consider the prospect of life preserved for over 4 billion ears on that planet in ice-cemented ground in the Southern Highlands. David was also active in international science. He actively participatedi n the International Permafrost Association, and he was eager to involve scientists from all over the world in his field expeditions. In addition, he participated in expeditions in many other countries and Antarctica. His strong yet gentle personality will be missed whenever there is drilling to be done searching for microbial life in ice-cemented ground. He was the first to develop the methods for drilling in permafrost without the use of drilling fluids, thereby preventing contamination of the core. He led a major international expedition to drill into ancient Siberian permafrost for microbial ni- vestigations. He was quite a phenomenon in the field, operating the permafrost drill nonstop in the24 hours of polar light.