"The Adventure of the Speckled Band" is written from the perspective of Dr. John Watson, Holmes's close friend and avid admirer, and through his eyes Doyle presents a picture of Sherlock Holmes as a genius whose "rapid deductions, as swift as intuitions," are a joy to observe. Watson allows himself to be hauled out of bed at seven-thirty in the morning in order to assist his friend, stating that he had "no keener pleasure" than in assisting him, observing the deductions which were "always founded on a logical basis with which he unravelled the problems" brought to him by his clients. Evidently, Holmes has a singular genius, and one which his companion, an educated medical man, finds singular among anyone he has ever met.

Subsequently, Watson presents an example of this deductive skill, which he has alluded to in the description of how Holmes explains to his visitor how he knows she has come in by train this morning. Helen Stoner's reaction to Holmes's reasoning—she "gave a violent start and stared in bewilderment"—demonstrates how shocking Holmes's deductive skill can appear to those who are unfamiliar with either it or him, a further indication that Holmes's is an uncommon genius.