The first nine books establish the high moral code of the West by which the decisions and attitudes on the X Bar X ranch are defined. The pillars of this code include respecting a man's privacy if he wants to keep his own counsel, supporting him if he asks for help, generosity to one's friends, fairness to one's enemies, scrupulous honesty in all dealings, accepting good fortune and bad as it comes your way, unquestioned loyalty to the boss, justice without vengeance, helping your neighbor while respecting his fences, hospitality to friends and strangers alike, and expecting the best from others while showing mercy when you don't get it. These virtues are the constant background to the action in these books, and mark its distinguishing characteristics. The code lags in some of the later books, and is seriously compromised in volumes 10 and 11, but is never completed eclipsed.

The philosophy behind these attitudes is rarely spelled out, but examples of the virtues are so abundant throughout the first nine volumes, and noticeable in the remainder, that they can easily be distilled from the action. In On Big Bison Trail, for example, one of the subplots involves Nick Looker, who is troubled when an impostor tries to claim an inheritance which is rightfully his. The casual record-keeping of the West makes the outcome doubtful. Although Nick is obviously disturbed, his fellows leave him alone until he is ready to tell them the problem. Once they are made aware of the need, they put enormous effort into seeing justice done. When Nick is offered an easy way to the inheritance by a crooked lawyer, he never wavers in his determination to get it honestly or not at all. Finally, once he comes out on top, he shares his bounty with his friends by "losing" to them through a poker game so as to preserve their dignity.

The series is notable also for strong doses of humor. Bunk house capers and family fun frequent most of the stories, not vital to the plot but essential for setting the atmosphere of the X Bar X ranch. The discriminating reader may detect a parallel to the hijinks of the boys in the early Hardy Boys series. The events described are not just comic relief but also provide the setting for important character development. The individuals are carefully and consistently sketched, and are well-delineated, with their personalities distinct and usually maintained throughout the series. The first nine volumes masterfully present this facet of the X Bar X series, but many of the later volumes maintain it admirably.

Focusing on the first nine volumes, we note that the humor is a tongue-in-cheek and clever style, sometimes subtle, usually evident in times of stress in the plot, and always wry. These excerpts from On Whirlpool River provide a few examples from an enormous store in the writing.

If they did come upon the bear, by great good luck Roy might succeed in placing a shot through the eye into the brain, which was the only place where the small bullet would be effective. If he missed—well, several things might happen, and not all of them to the bear.

(page 4)

"Who, me?" Nick's face expressed hurt surprise, "What have I done, boss?"