1910. Illustrated. This unusual and popular series tells vividly the story of four adventure-loving lads, who, with their guardian, spent their summer vacations in the saddle in search of recreation and healthful adventure. Long journeys over mountains, through the fastness of primitive forest and across burning desert, lead them into the wild places of their native land as well as into many strange and exciting experiences. There is not a dull moment in the series. Contents: A Mysterious Visitor; A Pack Mule Goes Over a Cliff; A Daring Proposal; Into the Canyon; Rescued by a Human Chain; Making the Best of It; Boy and Ponies Strangely Missing; The Indian Makes a Discovery; Horse Thieves Pay a Second Visit; The Professor Distinguishes Himself; Chunky Objects to Egg Water; All Gone But Two; Winning Through Pluck; Rescue Parties on the Trail; The Round Up; The Voice in the Rock; When the Dark Horse Won; Tad Wins a Roping Contest; and Wrecked in an Ore Car.