No. Only copies are placed on the shelf; your source objects are never moved or modified.

Yes. Add them to the Decorative list and choose what percent of levels get decoratives and how many books sit between each one.

Fill the first shelf, press Apply to bake it in place, then select the next shelf and press START. The source models never move and applied books stay put.

An older build mistakenly used a neighboring shelf as a ceiling. The current version only treats a surface as a ceiling when it is actually above that compartment, so open-top areas keep full-height books. Make sure you are on the latest version (remove the old add-on, restart Blender, then install the new file).

Lower the "Compartment gap" value in General settings so the divider is detected as a separation. If two separate units are being merged into one, raise the value instead.

Yes. Add as many models as you like. Each book is oriented and scaled from its own axes, so different models all stand correctly and uniformly. A built-in "bag" system spreads them evenly with no repeating pattern and no back-to-back duplicates.

Any shelf mesh works. The addon automatically detects each level and each separate compartment, so straight shelves, divided shelves, and multi-compartment units are all supported.