In the "_High School Boys' Vacation Series_" our readers have followed Dick & Co. through their summer pleasures and sports. In the first volume of this present series, "_The High School Boys' Canoe Club_," the adventures are described that fell to the lot of Prescott, Darrin, Reade and the others in the summer following their freshman high school year. In the second volume, "_The High School Boys In Summer Camp_," our readers found an absorbing narrative of the startling doings of Dick & Co. in the summer following their sophomore year. And now, in this present volume, we at last come upon our young friends at the beginning of their vacation season after the completion of their junior year, with its football victories. Now they are budding seniors, ready to enter the final, graduating class of Gridley High School in the coming autumn. As Dick looked into the faces of his chums he laughed. "So you don't like the push-cart idea, eh?" he demanded. "All right; if you fellows would rather loaf than eat-----" "We can hire a horse, and still have money enough left to eat," protested Tom. "See here, Dick, although fishing is great fun while it lasts, we shan't be out all summer on a fishing trip. We don't need such a lot of money for, say, only a two or three weeks' trip." "Yes; I think two or three weeks will see us in from our fishing trip," Prescott admitted. "But if we do come back early, fellows, then we shall need some other kind of a trip for August, won't we?" "Say, that's right!" cried Dave Darrin, his eyes glistening. "Fellows, we are troubled with wooden heads. While we've been thinking of nothing but a fishing trip in July, Dick has actually had the brains to figure out that we might like to go away on some other kind of outing in August." "Such an idea did occur to me," replied Dick. "What's the scheme for August, Dick?" demanded Greg eagerly. "Out with it!" insisted Hazelton. Dick shook his head. "Now, don't be mean," insisted Danny Grin. "Dick, you owe it to us, almost, to let us get a little look at the machinery that's moving in the back of your head." "I haven't an August plan---at least, not one that is clear enough for me to submit it and put it to vote before you," Dick went on. "Fellows, let's set about this present fishing trip, for this month, and then, while we're away, talk up the proper scheme for August. Whatever we do in the way of fun, next month, will be sure to be better planned if we wait a little before talking it over." "All right, then," agreed Tom Reade with a sigh. "But I warn you, Dick, and all you fellows, that if Prescott is too stingy with news about his August plan, I shall put forth one of my own." "What's your August plan, Tom?" demanded Greg. "I'm not going to tell you---yet," Reade rejoined, shaking his head mysteriously.