No, this is about "How AES encryption works". Emphasis mine. AES internals are interesting, but they're not specific to how AES encryption works. EG AES-CTR-DRBG is a CSPRNG using AES, not an encryption system. AES-CMAC is a MAC using AES, not an encryption system. AES can be used for lots of non-encryption tasks, so the author should have either dropped "encryption" from the title or included information on what's needed to turn AES from a block cipher into an encryption algorithm.