Computational Cognitive Neuroscience 3e (O'Reilly and Munakata)
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The content is organized into chapters, but also massively hyperlinked, and the content can go very "deep" while also enabling a very quick and relatively high-level of information that captures the key points, suitable for college undergraduates or even high school curricula. The main page for a given chapter provides a complete high-level pass through the material that stands alone, and is highly accessible. Everything else should be a subtopic page under the main page.
Thumbnail: Frontal lobe (in blue)/Lobes of the brain. (Public Domain; Henry Gray via Wikipedia)