I have understood and worked problems in all the contents of Wackerly's Mathematical Statistics With Applications 7th edition. In trying to work in other statistics courses, they all seem to assume I have already learned Fisher Information. In what class or textbook would I learn about it? Repeated searches on Google and here turned up nothing. I have bought multiple textbooks on statistics and they either don't mention it or assume I already know it.
In general, I'm struggling to understand the statistics curriculum; different classes seem to have almost a random assortment of topics: sampling, Bayesian inference, a dozen flavors of biostatistics all seemingly different, and so on. What text would you recommend to advance my understanding? I feel as if I have mastered "Stats 101" and I am looking for "Stats 102" so to speak. I would like to be able to understand (and tutor) statistics at a higher level than "blind plug and chug" aka "statistics as flowchart."