Originally posted by carrrlangas some good biblography
Herbert Keppler "The Pentax Way" He refers to DOF in a practical way throughout the book with simple diagrams. However, only for the 35mm film format
Arthur Cox " Photographic Optics" Pages 64 to 97. He shows the math with descriptions, geometric optics and lens diagrams. That book is pre- computer, however I use his functions in a spreadsheet.
A very simple but usable computer aided design application is "OpticalRayTracer.jar" it is GPL, free and runs on Java, so it is platform agnostic.
Here it is modeling a vintage 90mm wide angle lens at f/11 on a 4 x 5 film plane.
I can model that because the prescription is available, However I don't think the prescriptions for modern lenses are available in public domain?
The app models dispersion as well for lateral chromatic abberation, and it is possible to change things (for example the aperture), zoom into the film plane and see the circle of confusion.