Found on a book, brown head, long silvery body.
No interactions present.
...and probably L. bostrychophila, the most common one - but there are a whole stack of other species that turn up occasionally and need a microscope to recognise.
For more about these tiny creatures see:
Entomologist and biological recorder
Lat/Lng: 55.8821, -4.2828
OS grid ref: NS573677