Electrochemical Biosensors for miRNA Detection -- Electrochemical Detection of RNA.- DNA and PNA probes for DNA Detection in Electroanalytical Systems -- DNA for Non-Nucleic Acid Sensing -- Aptamers in Oncotherapy -- Genotyping of Single Nucleotide Polymorphism -- Environmentally Responsive and Bright Fluorescent Probes Possessing Dansyl-modified Oligonucleotides under Hybridization of DNA and RNA -- Fluorescent Nucleic Acid Analogues in Research and Clinical Diagnostics -- Emergent Properties and Functions of Nanoconfined Nucleic Acid Architectures -- RNA and DNA Diagnostics on Microspheres: Current and Emerging Methods -- DNA and RNA Electronic Properties for Molecular Modifications and Environmental State Diagnostics -- Mechanochemical Sensing.- Microarrays as Research Tools and Diagnostic Devices -- Quadruplex Priming Amplification (QPA) for Nucleic Acid Diagnostics.- Single-molecule strategies for DNA and RNA diagnostics -- Detection and Assessment of microRNA Expression in Human Disease. The aim of molecular diagnostics is preferentially to detect a developing disease before any symptoms appear. There has been a significant increase, fueled by technologies from the human genome project, in the availability of nucleic acid sequence information for all living organisms including bacteria and viruses. When combined with a different type of instrumentation applied, the resulting diagnostics is specific and sensitive. Nucleic acid-based medical diagnosis detects specific DNAs or RNAs from the infecting organism or virus and a specific gene or the expression of a gene associated with a disease. Nucleic acid approaches also stimulate a basic science by opening lines of inquiry that will lead to greater understanding of the molecules at the center of life. One can follow Richard Feynman's famous statement "What I cannot create, I do not understand.".