This is a TSR promotional flier from around 1980-1981, and sometimes shows up on Ebay with other items from the period. The first copy I had back in 2006 was found with a Cook/Marsh Expert Set (1981), and later I found another copy in an auction for a Holmes Basic Set.

The following is adapted from a review I originally posted on Dragonsfoot in 2006:

As noted by the "Odd Items" page on the collecting site the Acaeum, this minor artifact consists of a scant four sides. The first page features a great rendering, by Bill Willingham, of a spell-casting wizard on a rocky outcropping facing off against a flying, flame-breathing dragon. The large title reads, "YOUR PERSONAL INVITATION TO ADVENTURE" and the smaller subtitle reads, "UNDERSTANDING DUNGEONS & DRAGONS AND ADVANCED DUNGEONS AND DRAGONS FANTASY ADVENTURE GAMES". 

The second through fourth pages describe D&D games. No author is indicated anywhere in the document. The writing style is somewhat simplistic, more in the style Moldvay Basic Rulebook than Gygaxian. The editing is bit poor; for example, the paragraphs have an inconsistent number of blank lines between them.

Content-wise, the most interesting points are the examples of character creation and gameplay. One paragraph on the second page describes creation of a character named Rondel. With stats that read S17, I4, W6, D14, C16 and CH5, Rondel is described as "somewhat of an unintelligent, bumbling lout" and "no mental giant, he does enjoy far above the normal amounts of physical strength, stamina and skill." The author declares that Rondel would make a good fighter and "he will make an excellent member of an expedition as long as he receives good direction from a group leader."

About half of the third page is given over to an example of gameplay, which resembles the samples that are found in the early Basic rulebooks. It is introduced as "taken out of a beginning level of campaign" and tells the reader to "picture the lowest level of a crumbling, abandoned castle, where (rumor has it) a great fortune, spoils of a long forgotten crusade, lies buried. Our brave band of adventures [sic] has fought their way past a variety of traps and monsters which were left to guard the treasure and is now confronted with a new problem. In the dark and narrow stone-paved passageway they have been following, a new obstacle is encountered. They are wounded, exhaused and hungry, nonetheless, a decision must be made." Following this about ten lines of dialogue between the DM and two characters is given. The speaking characters are "Maria (an elven character)" and "Balek (a dwarven character)." Rondel makes a reappearance, and "Felton the cleric" is briefly mentioned. The obstacle turns out to be a "bottomless" twenty-foot wide pit, which they cross by swinging on a rope lassoed to a hook in ceiling (shades of Star Wars...) On the far side of the pit they are attacked by an angry cave bear. Rondel is bitten and misses his attack on the bear. Maria casts magic missile and "through the combined efforts of the party, the bear is beaten, but Rondel lies badly wounded and bleeding on the floor of the passageway. Felton the cleric, using skill and holy spells, heals the brave fighter. The exhausted party rests, gathering their strength for whatever terrors and treasures may lie ahead." Rondel makes one last appearance on page four where experience points are described and it is forecasted that he "might eventually wind up as a seasoned warrior and respected member of his society, if he remains alive." This encounter is sufficiently vague that it could describe a D&D or AD&D game; the cave bear is described in both Moldvay Basic and the Monster Manual.

I don't recognize these character names from any other D&D products. Rondel is a type of dagger used in the late Middle Ages.

The last half of the fourth page attempts to distinguish the Basic, Expert and Advanced game, but isn't particularly illuminating. The last part describing the Advanced game lists the five hardbound books available at the time (PH, MM, DMG, DDG, and FF), with a sentence describing each. The PH description states "everything a player needs to know to enter this world as a fighter, magic-user, illusionist or other adventurer...", which is a bit odd after the body of the text repeatedly mentioned fighters, magic-users and clerics (thieves are notably absent from any part of the text). Furthermore, the FIEND FOLIO seems to be a hasty addition to the 2nd print because there is no clear indication of the difference between the Monster Manual and FF (based on the mostly redundant descriptions, a novice might conclude that the FF is superior because it is "alphabetical" and most monsters are "illustrated").

The subtitle noted above indicates that YPITA is a successor to the earlier "Understanding Dungeons & Dragons" (UD&D) publication. I don't have a copy of UD&D, so I can't provide a comprehensive comparison. The Acaeum listing states that YPITA uses "simpler terminology", and I agree based on the single UD&D page shown there. It doesn't appear that YPITA was directly edited from the UD&D text. Someone with UD&D could confirm whether or not UD&D has any examples of play similar to YPITA.