"The Watcher by the Threshold" by John Buchan is a collection of supernatural tales published in 1902. Set primarily in the Scottish landscape, these stories blend ancient folklore with unsettling encounters. Characters discover hidden races in remote hills, pursue mystical islands beyond the western seas, and confront shadowy presences that haunt the threshold between reason and madness. Buchan weaves scholarly curiosity with creeping dread, exploring what happens when modern men stumble upon forces older and darker than civilization itself. (This is an automatically generated summary.)