Today's free book is Celtic Folklore: Welsh And Manx (in 2 volumes) by John Rhys. For the table of contents, check at the bottom of this post below the image.
The book is available at Sacred Texts, Internet Archive: Vol. I and Vol. II, Hathi Trust, and Google Books: Vol. I and Vol. II.
Volume I
Preface
Chapter I: Undine's Kymric Sisters
Chapter II: The Fairies' Revenge
Chapter III: Fairy Ways and Words
Chapter IV: Manx Folklore
Chapter V: The Fenodyree and his Friends
Volume II
Chapter VI: The Folklore of the Wells
Chapter VII: Triumphs of the Water-World
Chapter VIII: Welsh Cave Legends
Chapter IX: Place-Name Stories
Chapter X: Difficulties of the Folklorist
Chapter XI: Folklore Philosophy
Chapter XII: Race in Folklore and Myth