It's a little hard to say much about a book where so much has already been said. This is one of Arthur Machen's best short story collections and I recommend it heartily. Consisting of his masterful "The Great God Pan" novella and others, this collection gives an excellent overview of macabre writing at the turn of the century. Full of Victorian shudders.
Few writers have ever been able to make the ordinary so supernatural. In Machen's writing, there's always the survival of something ancient and evil behind every bush and shrub.