Overall I enjoyed the premise of Cocaine Blues more than the book itself. I definitely was a fan of the setting, 1920s Australia is a setting I have never read before that I can recall. Plus the 1920s in general is a fun setting.
My main problem arises in the main character of Phryne and the mystery. Phryne is what I would consider like Nancy Drew: too good at everything for no reason. Plus being "too good" is just damn boring. Why, for instance, is Phryne able to accomplish things so much easier than the freakin' police? Either the police were especially terrible at their job or Phryne is especially good. (The whole use of "especially" is a dead giveaway that it isn't a preferred situation for a reader.) Apparently the lucky guess at the beginning of the novel when Phryne solves her first mystery of the series was just a setup for how all the mysteries would go. Overall things came together too easily and neatly for Miss Fisher and there were too many coincidences for me to not roll my eyes at.
I also found the overall speed of the novel slow, except for when something would suddenly happen and things would be tied up in a paragraph. Spreading out the interesting parts would have been preferred. The party scenes absolutely dragged on for me and the dialogue overall was rather bland as well.
One plus of the novel was Dr. MacMillan, a tough female doctor from Scotland. I liked the feminist aspect included, especially when it came to the doctor's scenes. However, they were too little and far between to help the book much. I also question why the hell Phryne sent the white powders she collected to the hospital and MacMillan to be analyzed? Really? This is far-fetched.
If Phryne had been less like Nancy Drew, had everyone been better characterized and had the setting played a major role I think this would have been a winner. Unfortunately I'm just not a fan of Nancy Drew.