This is a very neat resource, empowering fantasy GMs to let players see what their characters do.
It's very simple. For each location there is a page with a sketch map, an elevation view and space for the GMs notes. This is followed by full-page versions of the sketch map and side elevation, both of which are done in 'freehand pen and ink' style. The GM can chose to display either or both as appropriate to supplement a verbal description or just saying "This is what you see" and letting the players draw their own conclusions.
This volume contains various lairs likely to be used by monsters or other creatures probably encountered in the wilderness areas of your campaign world. It's up to you to decide who lives there now... not to mention who originally constructed the lair and any other details you wish to throw in.
The suggested uses are an ankheg’s tunnels, a barghest’s den, an ettercaps’ nest, a ghouls’ tomb, a gnolls’ pit, a goblins’ watchtower, a hag’s hut, an ogre’s lair, a kobolds’ camp, and a koa-toas’ ziggurat; but as there is no labelling whatsoever it's open to you to put them to different uses if that suits your purposes better.
A neat resource to have to hand should you have need of this type of location.