There are ups and downs in this series, and these additions illustrate the extremes. Mr. Coombs' detective stories are superior to his recent sport stories, as his quick-on-the-trigger heroes are too busy snaring bad guys to indulge in moral reflection. His settings offer wide range, - circus, zoo, an old mine, a haunted house, his pace is good, his plots varied. Reliable fare....Mr. Payne's young men, on the other hand, are sad-faced, poverty-striken little souls, who outwit the bullies and other unpleasant adults by an incredible excess of moral stamina. Details of roundups and rodeos incidental to the boys winning their spurs keep young readers turning pages.