In this story Watson seems to know all about Professor Moriarty. However, in 'The Final Problem' he claims complete ignorance of the villain's existence. Odd, isn't it?

this is a personnal favorite of mine. I don't really know why, but I liked the slight snobbism of English criminals being better then American ones, and I liked Watson's off base suspicions and Holmes's questions, which as usual go un answered by all.

It's kind of a formula, isn't it? Holmes points out everyone's attention to some small detail, and everyone ignores it, even thought it is the solution for the puzzle.

This is also my personal favorite Holmes story. Part two, which details Douglas/McMurdo's adventures in the Valley of Fear may be the best thing Doyle's ever written.
It's interesting that Moriarty has become such a well-remembered character, since this is the only Holmes story by Doyle besides "The Final Problem" in which he figures. And in this one, he's in a completely offstage role.

Dear me, Mr. Holmes! Dear me!

The code Porlock uses in his message to Holmes is problematic in more ways than one. In the first place, of what use is a code that makes no provisions for proper nouns? Isn't anyone in Moriarity's organization who might intercept the message and see in plain english the words "DOUGLAS" and "BIRLSTONE" written going to know immediately what the missive pertains to? Also, Porlock later sends a message to Holmes advising him that he may be under suspicion and to ignore and destroy the coded message - but this no less incriminiating message he writes in PLAIN UNCODED ENGLISH!

Didn't Moriarty appear in many of the movies?

Merat: Didn't Moriarty appear in many of the movies?

I've been watching the Jeremy Brett movies lately. It's interesting that Moriarty is added in to "The Red-Headed League," as the force behind John Clay's attempted theft of the 60,000 napoleons from the Coburg branch bank. Moriarty has a few scenes and announces his intent to "make [Holmes] an offer he can't refuse," after Holmes & Co. thwart the bank robbery. It actually works really well.

The interesting thing is that, in this series, "The Final Problem" is the very next story shown. No doubt the producers feared that viewers would not like to see Holmes "killed" by someone whom they'd never heard of; hence, the need to insert Moriarty into the preceding story.