This study presents a comprehensive transcriptional atlas of the prenatal human brain, providing a detailed resource for understanding human brain development. The atlas includes de novo reference atlases, in situ hybridization, ultra-high resolution MRI, and microarray analysis of highly discrete brain regions. It reveals transcriptional differences in developing cerebral cortex layers, with laminar signatures reflecting cellular composition and developmental processes. Molecular correlates of cytoarchitectural differences between human and mouse brains are identified, including species-specific gene expression in subplate regions. Fronto-temporal gradients are observed in both germinal and postmitotic cortical layers, with particular enrichment in the frontal lobe. Many genes associated with neurodevelopmental disorders and human evolution show patterned expression, potentially underlying unique features of human cortical development. The data provide a rich, freely accessible resource for studying human brain development. The human brain develops through a complex series of histogenic events regulated by gene expression, and disruptions can lead to severe consequences. Most developmental studies are conducted in mice or non-human primates due to limited access to human prenatal tissue. However, significant species differences exist, necessitating human brain studies. The human neocortex has undergone massive expansion, particularly in superficial layers, likely due to differences in progenitor pool expansion during neurogenesis. The subventricular zone (SZ) is present in all mammals but is split into outer and inner regions in primates. The transient subplate zone (SP) is greatly expanded in humans, as is the subpial granular zone (SG). Species differences in the developmental origin of cortical GABAergic interneurons are also observed, with human cortical interneuron origins remaining controversial. Understanding cortical specialization for language can only be studied in humans. Recent studies have analyzed the developing brain and neocortical transcriptome, identifying genes differentially expressed between major regions, including those associated with human-accelerated conserved noncoding sequences. Expression varies between cell populations, and detailed analysis of fetal mouse neocortex layers found thousands of genes differentially expressed. Species differences in distinct fetal transient zones, including the SZ, SP, CP, and SG, have also been described. The goal of the current project was to create resources for studying prenatal human brain development and the early roots of neurodevelopmental and psychiatric disorders. These include anatomical reference atlases and detailed transcriptional profiling of normal mid-gestational brain. These data are freely accessible via the BrainSpan Atlas of the Developing Human Brain. The study analyzed four mid-gestational human brains, creating detailed de novo reference atlases and transcriptome datasets. The entire left hemisphere of each specimen was cryosectioned for laser microdissection, with slides for histological staining and in situ hybridization. Approximately 300 anatomical regions per specimen were isolated for RNA isolation and microarray analysis. These data were anatomically delineated to create digital reference atlases, allowing the representation of transcriptome data in native anatomicalThis study presents a comprehensive transcriptional atlas of the prenatal human brain, providing a detailed resource for understanding human brain development. The atlas includes de novo reference atlases, in situ hybridization, ultra-high resolution MRI, and microarray analysis of highly discrete brain regions. It reveals transcriptional differences in developing cerebral cortex layers, with laminar signatures reflecting cellular composition and developmental processes. Molecular correlates of cytoarchitectural differences between human and mouse brains are identified, including species-specific gene expression in subplate regions. Fronto-temporal gradients are observed in both germinal and postmitotic cortical layers, with particular enrichment in the frontal lobe. Many genes associated with neurodevelopmental disorders and human evolution show patterned expression, potentially underlying unique features of human cortical development. The data provide a rich, freely accessible resource for studying human brain development. The human brain develops through a complex series of histogenic events regulated by gene expression, and disruptions can lead to severe consequences. Most developmental studies are conducted in mice or non-human primates due to limited access to human prenatal tissue. However, significant species differences exist, necessitating human brain studies. The human neocortex has undergone massive expansion, particularly in superficial layers, likely due to differences in progenitor pool expansion during neurogenesis. The subventricular zone (SZ) is present in all mammals but is split into outer and inner regions in primates. The transient subplate zone (SP) is greatly expanded in humans, as is the subpial granular zone (SG). Species differences in the developmental origin of cortical GABAergic interneurons are also observed, with human cortical interneuron origins remaining controversial. Understanding cortical specialization for language can only be studied in humans. Recent studies have analyzed the developing brain and neocortical transcriptome, identifying genes differentially expressed between major regions, including those associated with human-accelerated conserved noncoding sequences. Expression varies between cell populations, and detailed analysis of fetal mouse neocortex layers found thousands of genes differentially expressed. Species differences in distinct fetal transient zones, including the SZ, SP, CP, and SG, have also been described. The goal of the current project was to create resources for studying prenatal human brain development and the early roots of neurodevelopmental and psychiatric disorders. These include anatomical reference atlases and detailed transcriptional profiling of normal mid-gestational brain. These data are freely accessible via the BrainSpan Atlas of the Developing Human Brain. The study analyzed four mid-gestational human brains, creating detailed de novo reference atlases and transcriptome datasets. The entire left hemisphere of each specimen was cryosectioned for laser microdissection, with slides for histological staining and in situ hybridization. Approximately 300 anatomical regions per specimen were isolated for RNA isolation and microarray analysis. These data were anatomically delineated to create digital reference atlases, allowing the representation of transcriptome data in native anatomical