Toto's Adventures with Dorothy, as told by Toto, is the true tail of their exploits in the Land of Oz.
Although Toto can articulate his thoughts and obseravations cleary to the reader, it is when he attempts to verbalize them to his companions that he finds himself happered by his thick canine accent. In other words, he barks.
Toto nonetheless offers his advice whenever they find themselves in one perilous mishap after another. For without Toto's courage, foresight, and determination, as far as he is concerned, they could all still be wandering futility through the the Land of Oz. Or worse, slain by the any of the evil threats they encounter.
When told that the Wizard of Oz never appears in his true form, and presuming that Wizards are mostly likely courageious, brilliant, generous to a fault, and the best compaion one could every wish for, Toto concluded that the Wiard's true form is most certainly a breed of dog. A Cairn terrier, perhaps? Having ascertained this knowledge by deduction, Toto was eager to meet snout to snout what he envisioned as the Great Wizard Dog!