This is a feature of some online catalogs where it lists adjacent books on the shelf. This is usually done by the call number, so it basically just lets you see what the previous and next call numbers are. Given that the call numbers are usually within some sort of classification scheme, this is a quick way to find related material.

For example, consider this book at the University of Maryland's library:

https://umaryland.on.worldcat.org/oclc/1594752

Scroll down to the bottom to see "Browse the Shelf". Notice that the call numbers are sequential.

The Library of Congress has a similar feature even though only librarians are able to access the stacks:

https://catalog.loc.gov/vwebv/searchBrowse

I don't mean to come off as dismissive of the feature. It is pretty useful! But I also value shelf access and just being able to dig into a book at a moment's notice.

Thank you for explaining it so well. Some libraries also have digital versions, allowing you to effectively browse the stacks from anywhere. The feature can and should be improved as it's a bit clunky. Digitization is a slow process, but we'll get there eventually. For now, we have growing pains.

Thanks!

The library of congress version is currently unavailable, perhaps it's gotten too much traffic from HN!

the umaryland version, @sheepshear do you personally find this feature useful, you use this feature? Or you were just giving it as an example for others who might want it?

Either way, this is a good example of the kind of "browse shelf" feature you were speaking of, looking more or less like this?

I suggested it because I've used it.