The study introduces seqFISH+, a method that enables high-resolution imaging of the transcriptome in single cells with sub-diffraction-limit resolution. This technique uses a standard confocal microscope and allows the visualization of mRNA for up to 10,000 genes in tissues such as the mouse brain cortex, subventricular zone, and olfactory bulb. seqFISH+ overcomes the challenge of optical crowding by using a combination of sequential hybridization and pseudocolor imaging, which allows for the resolution of individual mRNA molecules. The method enables the unbiased identification of cell classes and their spatial organization, as well as the detection of subcellular mRNA localization patterns and ligand-receptor interactions between neighboring cells. seqFISH+ provides a significant improvement over existing methods by enabling the profiling of a larger number of mRNAs and generating more accurate RNA barcodes. It allows for the creation of spatial cell atlases and the discovery of biological processes in situ. The method is robust and can be applied to various tissues, including the brain, where it reveals detailed information about the spatial organization of different cell types and their gene expression patterns. seqFISH+ also enables the identification of new cell types and the analysis of gene expression in a cell-specific manner, which is crucial for understanding developmental processes and cell fate decisions. The study demonstrates that seqFISH+ can be used to analyze the spatial organization of the olfactory bulb and the subventricular zone, identifying distinct cell types and their interactions. It also reveals the spatial relationships between different cell types and the expression patterns of genes in these cells. The method is capable of detecting ligand-receptor pairs in neighboring cells, which are not available in dissociated cell analysis. seqFISH+ provides a powerful tool for spatial genomics, enabling the discovery of novel targets in disease samples and the development of precise spatial-genomics and single-cell based diagnostics. The method is efficient, with an 8-fold reduction in imaging time compared to other techniques, and can be generalized to other applications such as chromosome and protein imaging.The study introduces seqFISH+, a method that enables high-resolution imaging of the transcriptome in single cells with sub-diffraction-limit resolution. This technique uses a standard confocal microscope and allows the visualization of mRNA for up to 10,000 genes in tissues such as the mouse brain cortex, subventricular zone, and olfactory bulb. seqFISH+ overcomes the challenge of optical crowding by using a combination of sequential hybridization and pseudocolor imaging, which allows for the resolution of individual mRNA molecules. The method enables the unbiased identification of cell classes and their spatial organization, as well as the detection of subcellular mRNA localization patterns and ligand-receptor interactions between neighboring cells. seqFISH+ provides a significant improvement over existing methods by enabling the profiling of a larger number of mRNAs and generating more accurate RNA barcodes. It allows for the creation of spatial cell atlases and the discovery of biological processes in situ. The method is robust and can be applied to various tissues, including the brain, where it reveals detailed information about the spatial organization of different cell types and their gene expression patterns. seqFISH+ also enables the identification of new cell types and the analysis of gene expression in a cell-specific manner, which is crucial for understanding developmental processes and cell fate decisions. The study demonstrates that seqFISH+ can be used to analyze the spatial organization of the olfactory bulb and the subventricular zone, identifying distinct cell types and their interactions. It also reveals the spatial relationships between different cell types and the expression patterns of genes in these cells. The method is capable of detecting ligand-receptor pairs in neighboring cells, which are not available in dissociated cell analysis. seqFISH+ provides a powerful tool for spatial genomics, enabling the discovery of novel targets in disease samples and the development of precise spatial-genomics and single-cell based diagnostics. The method is efficient, with an 8-fold reduction in imaging time compared to other techniques, and can be generalized to other applications such as chromosome and protein imaging.