The July 21, 1923 issue of The Pharmaceutical Journal and Pharmacist[1] (No. 3118 Vol. 111 or 4th series Vol. 57) contains on page 61 a review of The Mysterious Affair at Styles which Christie would later recall as one of the reviews which pleased her the most.
The review is by an anonymous contributor but one who is obviously a pharmacist. He calls Styles a first rate detective story which is hard to put down. From a professional point of view, he points out that the particular interest it has for pharmacists is that it is a poisoning case. He laments that "Such cases as we pharmacists find within the covers of a novel are, as a rule, apt to offend our professional instincts...." but Styles, by contrast, is a notable exception. He notes that "This novel has the rare merit of being correctly written--so well done, in fact, that we are tempted to believe either that the author had a pharmaceutical training or had called in a capable pharmacist to help her over the technical part." Therefore "the pharmacist reader's susceptibilities are not offended at any stage of the story, and as a consequence, he finishes thenovel with all the satisfaction of having come across a real good detective story with a professional favour about it."
Writing in An Autobiography, Christie noted that while she had a few nice reviews for Styles, the review in the Pharmaceutical Journal pleased her the best. She quotes the review as saying that "this detective story for dealing with poisons in a knowledgeable way, and not with the nonsense about untraceable substances that so often happens. Miss Agatha Christie ... knows her job". These words have often been re-quoted and one might even find them, for example, on Amazon among the reviews for Styles and attributed to the Pharmaceutical Journal. Strangely, an examination of the original review shows that these words are not there.[2] So Christie might have recalled incorrectly and might have been thinking of another review, or there might have been another review in the Pharmaceutical Journal that has yet to come to light.