There were three ways to establish jurisdiction over someone prior to International Shoe.
1. D is domiciled in the state
2. Service of process within the state (even if presence within the state was transatory)
3. Consent to forum.
With International Shoe, the "Minimum Contacts" such that "traditional notions of fair play and substantial justice" are not offended notion was established. This allowed to court to exercise jurisdiction over people and corporations not currently in the forum.
McGee v. Int'l Life the concept of jurisdiction based on a single activity is established. (ie. Specific Jurisdiction) If the suit is about the single activity that establishes D's contacts, then the suit is proper. If it the limited activity is NOT the topic of the suit, the suit is improper (see the "purposeful availment" arguement from Hanson v. Denkla)
I look at it like a matrix of sorts...
|Systematic and Continuous Activity||Single Activity|
|Suite Arises From Activity||General Jurisdiction||Specific Jurisdiction (McGee v Int'l Life)|
|Suit is unrelated to Activity||General Jurisdiction (Perkins v. Benquet)||No Jurisdiction (Hanson v. Denckla)|
(for some reason I couldn't make lines in the table, so you'll just have to imagine them...