Real-time quantitative PCR has revolutionized the field of quantitative PCR by eliminating many of the tedious and time-consuming aspects of traditional methods. Early quantitative PCR techniques required ensuring that the PCR was within the linear range of amplification and finding a suitable method to detect the product. Researchers used various methods such as serial dilutions of cDNA, altering amplification cycles, adding competitor templates, and using PCR mimics. Detection of the amplicon typically involved running gels and using stains, radioactivity, or probes. Real-time PCR allows for data generation within 2-3 hours, with advantages including enhanced sensitivity, high throughput, a closed-tube system, reduced variation, simultaneous multiplexing, and no post-PCR manipulations. The technology for real-time PCR has been available for over five years, with a significant increase in use over the past two years. The issue presents nine articles on real-time PCR techniques for quantifying DNA or RNA, including methods for quantifying cytokine gene expression, absolute and relative quantification, and the 2^-ΔΔCt method for relative gene expression. The article by Giulietti et al. describes the methodology for quantifying cytokine gene expression using real-time PCR, including an overview of the technology and probe chemistries. Absolute quantification determines the exact template copy number, while relative quantification compares expression levels to a control. The 2^-ΔΔCt method is discussed, along with its variations and data analysis tips. Real-time PCR is ideal for validating results from high-throughput technologies like cDNA microarrays and differential display PCR. The article by Rajeevan et al. describes a real-time PCR assay using SYBR green detection and melting curve analysis to validate these results. MethylLight is a real-time PCR assay for detecting DNA methylation patterns, which has been used to detect aberrant methylation in cancer cells. Real-time PCR has also improved the analysis of archival biopsies, allowing for the detection of specific tissue portions. The article by Lehmann and Kreipe discusses the use of laser-assisted microdissection with real-time PCR for FFPE biopsies. Real-time PCR has also been used for allelic discrimination and SNP detection, with applications in genetic analysis. Real-time PCR has enhanced both routine quantitative analysis and high-throughput screening capabilities. The combination of real-time PCR and molecular beacons allows for the detection of SNPs, which is important in determining disease susceptibility and drug response. Real-time multiplex PCR allows for the simultaneous detection of multiple PCR products, with applications in allelic discrimination and mutation screening. Real-time PCR is a major tool in quantifying viral load, with applications in various species. The article by Niesters describes the use of real-time PCR for quantifying viral load, including the NASBA technology for RNA amplification. The development of real-time PCR has enabled scientists to ask fundamental questions in a straightforward and automated manner, setting the foundation forReal-time quantitative PCR has revolutionized the field of quantitative PCR by eliminating many of the tedious and time-consuming aspects of traditional methods. Early quantitative PCR techniques required ensuring that the PCR was within the linear range of amplification and finding a suitable method to detect the product. Researchers used various methods such as serial dilutions of cDNA, altering amplification cycles, adding competitor templates, and using PCR mimics. Detection of the amplicon typically involved running gels and using stains, radioactivity, or probes. Real-time PCR allows for data generation within 2-3 hours, with advantages including enhanced sensitivity, high throughput, a closed-tube system, reduced variation, simultaneous multiplexing, and no post-PCR manipulations. The technology for real-time PCR has been available for over five years, with a significant increase in use over the past two years. The issue presents nine articles on real-time PCR techniques for quantifying DNA or RNA, including methods for quantifying cytokine gene expression, absolute and relative quantification, and the 2^-ΔΔCt method for relative gene expression. The article by Giulietti et al. describes the methodology for quantifying cytokine gene expression using real-time PCR, including an overview of the technology and probe chemistries. Absolute quantification determines the exact template copy number, while relative quantification compares expression levels to a control. The 2^-ΔΔCt method is discussed, along with its variations and data analysis tips. Real-time PCR is ideal for validating results from high-throughput technologies like cDNA microarrays and differential display PCR. The article by Rajeevan et al. describes a real-time PCR assay using SYBR green detection and melting curve analysis to validate these results. MethylLight is a real-time PCR assay for detecting DNA methylation patterns, which has been used to detect aberrant methylation in cancer cells. Real-time PCR has also improved the analysis of archival biopsies, allowing for the detection of specific tissue portions. The article by Lehmann and Kreipe discusses the use of laser-assisted microdissection with real-time PCR for FFPE biopsies. Real-time PCR has also been used for allelic discrimination and SNP detection, with applications in genetic analysis. Real-time PCR has enhanced both routine quantitative analysis and high-throughput screening capabilities. The combination of real-time PCR and molecular beacons allows for the detection of SNPs, which is important in determining disease susceptibility and drug response. Real-time multiplex PCR allows for the simultaneous detection of multiple PCR products, with applications in allelic discrimination and mutation screening. Real-time PCR is a major tool in quantifying viral load, with applications in various species. The article by Niesters describes the use of real-time PCR for quantifying viral load, including the NASBA technology for RNA amplification. The development of real-time PCR has enabled scientists to ask fundamental questions in a straightforward and automated manner, setting the foundation for