P: Navigate through "image view history" by using forward/backward buttons on mouse/keyboard

Which conditions would trigger adding an image to the back/forward history?  Making it most-selected among all selected images; viewing in Library Loupe; editing it in Develop; viewing it individually Slideshow, Book, or Web?  

When you go back, does it change to the module in which you viewed the image?   E.g. you view an image A in Develop, then switch to Library to view another image B, then hit Back -- does it switch back to Develop to show image A or does it show A in Loupe in Library?

(This might be something I could implement in Any Source...)

Thanks @johnrellis for that extensive answer! Unfortunately though, none of these options is what I am missing in Lightroom. I might be working on different images at the same time, switching back and forth between them. They may be in the same folder/collection or could be elsewhere. Yes, I could assign them a rating/color and filter by that, but that's not really practicable I believe. I'm aware of the Undo/Redo functionality of course, but as you already mentioned, moving around in the catalogue is not really the purpose of that.

Maybe it's just me, but using the mouse's back and forward buttons to navigate through the image view/edit history is kind of super intuitive to me. Let's say I click images 5 in folder A, image 57 in folder B, 37 in collection C and 546 in some filter result - and now I want to go back to that image 57 in folder B. Clicking that back button twice seems much easier to me than applying a filter or navigating through the folder structure. I believe it's quite a simple change with great benefit.

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There are several flavors of navigational history for moving among past-viewed images (keyboard shortcuts for your system are displayed on the corresponding menu commands):

Edit > Undo/Redo: The undo history includes pretty much everything you do in LR. But it's dangerous to use it like a browser back button to navigate to past-viewed photos, since it will undo edits, metadata changes, changes to collections, etc.

Window > Go Back / Forward: These commands maintain a history of the 20 last used sources (folders and collections) and move through that history.  They also appear as arrows in the upper-left corner of the filmstrip:

Window > Go Back To Previous Module: Flips back and forth between the two most recently used modules.

In addition to these built-in features, the Any Source plugin maintains a history of combinations of source (folder/collection), filter settings, and selection. Those of us with large archival catalogs rely heavily on filters for accessing photos, so the plugin's Back and Forward command let us dive into the catalog to find particular photos and then pop back up to where we were, restoring the original source, filter, and selection.