We address the following research questions: How can aptamer technology be used to understand biological phenomena? How can nucleic acids be exploited as drugs or drug targets to develop novel diagnostic and therapeutic applications? What are the underlying principles of nucleic acid evolution in the test tube and how can these be employed to generate novel compounds? To address these and other questions, we utilize in vitro selection procedures, in combination with chemical, biochemical, immunological, neurological and molecular cell biology techniques. Our overall goal is to develop molecular tools that alllow us to investigate biological systems with high precision. These tools also represent the foundation for implementing novel diagnostic and therapeutic strategies.