I will stick by my earlier strong recommendation of Vision Science - Photons to Phenomenology by Stephen Palmer. It is still my go-to textbook but, as I mentioned earlier, it is big and kind of pricey at $80 on Amazon. Please see my 18 June post for a convenient direct link to the proper Amazon page.
Let me mention two additional books that are more modest in depth but which cover the full scope of this blog and are less expensive.
The first is Perception by Irvin Rock. He was a pioneer in vision science. In this book he has described visual perception in very lucid terms. It has the kind of clarity that only comes from someone deeply experienced in their field. The paperback version is very reasonably priced on Amazon. I bought mine used for under $6, including postage. I highly recommend the book.
The second book is Cognition and the Visual Arts by Robert Solso. It is a less rigorous treatment of visual perception but it smoothly bridges the full scope of this blog, from vision through aesthetics. It is an easy and interesting read.