Vladimir Propp extended the Russian Formalist approach to narratology (the study of narrative structure). Where, in the Formalist approach, sentence structures had been broken down into analysable elements - morphemes - Propp used this method by analogy to analyse folk tales. By breaking down a large number of Russian folk tales into their smallest narrative units - narratemes - Propp was able to arrive at a typology of narrative structures. By analysing types of characters and kinds of action, Propp was able to arrive at the conclusion that there were thirty-one generic narratemes in the Russian folk tale. While not all are present, he found that all the tales he analysed displayed the functions in unvarying sequence.
   Try applying these to Star Wars or episodes of X-Files or Star Trek - It can be interesting to see how powerful are the narrative structures of folk mythology, and how they are continually reinserted into contemporary popular culture. The functions he described were as follows:

   After the initial situation is depicted, the tale takes the following sequence:
1.-A member of a family leaves home (the hero is introduced);
2.-An interdiction is addressed to the hero ('don't go there', 'go to this place');
3.-The interdiction is violated (villain enters the tale);
4.-The villain makes an attempt at reconnaissance (either villain tries to find the children/jewels etc; or intended victim questions the villain);
5.-The villain gains information about the victim;
6.-The villain attempts to deceive the victim to take possession of victim or victim's belongings (trickery; villain disguised, tries to win confidence of victim);
7.-Victim taken in by deception, unwittingly helping the enemy;
8.-Villain causes harm/injury to family member (by abduction, theft of magical agent, spoiling crops, plunders in other forms, causes a disappearance, expels someone, casts spell on someone, substitutes child etc, comits murder, imprisons/detains someone, threatens forced marriage, provides nightly torments); Alternatively, a member of family lacks something or desires something (magical potion etc);
9.-Misfortune or lack is made known, (hero is dispatched, hears call for help etc/ alternative is that victimised hero is sent away, freed from imprisonment);
10.-Seeker agrees to, or decides upon counter-action;
11.-Hero leaves home;
12.-Hero is tested, interrogated, attacked etc, preparing the way for his/her receiving magical agent or helper (donor);
13.-Hero reacts to actions of future donor (withstands/fails the test, frees captive, reconciles disputants, performs service, uses adversary's powers against them);
14.-Hero acquires use of a magical agent (directly transferred, located, purchased, prepared, spontaneously appears, eaten/drunk, help offered by other characters);
15.-Hero is transferred, delivered or led to whereabouts of an object of the search;
16.-Hero and villain join in direct combat;
17.-Hero is branded (wounded/marked, receives ring or scarf);
18.-Villain is defeated (killed in combat, defeated in contest, killed while asleep, banished);
19.-Initial misfortune or lack is resolved (object of search distributed, spell broken, slain person revivied, captive freed);
20.-Hero returns;
21.-Hero is pursued (pursuer tries to kill, eat, undermine the hero);
22.-Hero is rescued from pursuit (obstacles delay pursuer, hero hides or is hidden, hero transforms unrecognisably, hero saved from attempt on his/her life);
23.-Hero unrecognised, arrives home or in another country;
24.-False hero presents unfounded claims;
25.-Difficult task proposed to the hero (trial by ordeal, riddles, test of strength/endurance, other tasks);
26.-Task is resolved;
27.-Hero is recognised (by mark, brand, or thing given to him/her);
28.-False hero or villain is exposed;
29.-Hero is given a new appearance (is made whole, handsome, new garments etc);
30.-Villain is punished;
31.-Hero marries and ascends the throne (is rewarded/promoted).