This page attempts to list the mysteries of Lost chronologically through the series. As a mystery arises in an episode, provide a highlighted entry for it here to identify it as an outstanding mystery. If you have any theories regarding unanswered mysteries then place them against the mystery but as it's only a theory, leave the mystery highlighted.

Once a mystery has been solved, cite the episode which reveals the resolution and un-highlight the original entry. This way we will have a quick reference for all outstanding mysteries that have yet to be resolved.

As an example, in episode 1.01 we learn of the plane crash, we have no idea what caused it so we put an entry in under 1.01 Pilot : Part 1 suggesting the reason for the crash as unexplained. In series 2 episode 23 we learn the cause of the crash so we can cite that and un-highlight the original reference. Similarly, we also learn of the monster through the noises and the pilots death but we have no idea what it is. Hence this remains a mystery until we find out hopefully in series 4 rather than 6 ;P

The above examples are inserted below as a starter and I am going to re-watch all episodes to fill it in over the coming weeks. Any help would be appreciated.

Episode	Mystery	Theory / Solution
1.01 Pilot : Part 1	What caused the plane to crash?	2.23 Live Together, Die Alone - we learn from Desmond, after he studies some previous computer printouts, that he had in fact caused the crash by not pushing the button in time on the day of the crash.
	What is the monster that killed the pilot and generated the noises, crashing trees etc?
	Where on earth, literally, have they crashed?
1.02 Pilot : Part 2	How come there was a polar bear on a hot pacific island?	The Dharma Initiative were doing experiments on animals in their zoo facility called THE HYDRA.
	Where is the transmission coming from? Who recorded it?	The transmission is coming from a radio tower on the island. 1.09 Solitary - Sayid learns that Danielle Rousseau recorded it after she captured him
1.03 Tabula Rasa	What has Kate done to be being escorted back from Sydney by a US Marshal?	Kate kills her father by exploding his house, then goes on the run. The Marshall tracks her to Australia and finally catches her there.
1.04 Walkabout	What caused Locke to lose the use of his legs prior to the flight and how did he get the use of them back on the island?	Locke was pushed out a window by his own father, which he survived but as a result was paralized. He gets the use of them back because the island has a mystical ability to heal people who habitate it.
	Was it the 'Monster' that confronted Locke when he was boar hunting and if it was, why didn't it kill him like the pilot?
1.05 White Rabbit	Did Jack actually see his Dad or an apparition. If the former then how? Was Christian/Apparition leading Jack to water?
	Was the coffin empty because Jack's Dad was not in it when the flight took off or because 'he' came back to life and left it after the crash thereby explaining why Jack saw him?
	Where did 'Adam and Eve' come from (Jack said 40/50 years for their clothes to deteriate to how they were)? What are the black and white stones they had?
1.07 The Moth	Who took out Sayid when he was trying to triangulate the signal?	1.21 The Greater Good - Locke admits to Sayid that he was the one who took him out
1.09 Solitary	What is the power line Sayid found on the beach?	The power line leads to an underwater Dharma station called The Looking Glass which can jam all signals going out or coming in to the island.
	Who are the Others that Danielle Rousseau refers to?	At first we thought the Others were Dharma poeple but later find out that they are actually people who were there way before Dharma. The Dharma people called them Hostiles, that is until the Hostiles killed all the Dharma people.
	What is the Black Rock?	1.24 Exodus: Part 2 - It's a ship, strangely found approximately 2 miles inland.
	What was the whispering Sayid heard in the woods?
1.10 Raised by Another	Who attacked Claire in her sleep?	1.11 All the Best Cowboys Have Daddy Issues - We learn from events that Ethan was the one who attacked Claire in her sleep, he also went on to abduct her and hang Charlie leaving him for dead.
1.11 All the Best Cowboys Have Daddy Issues	Why did Ethan abduct Claire?	Ethan was injecting Claire with some sort of medications and was hoping to deliver her baby and then steal it for experiments.
	How did Locke predict it was about to rain so precisely?
	What's the metal sheet that Locke and Boone found just under the ground when searching for Charlie and Claire?	1.13 Hearts and Minds - Having cleared some of the dirt and earth from around it, it appears to be some form of hatch.
1.12 Whatever the Case May Be	Who was it that the toy plane belonged to?	1.22 Born to Run - We learn though Kate's flashbacks that it belonged to a childhood friend of hers called Tom, a doctor whom she got killed while tryng to run from the police.
	What is the film that the lyrics Shannon deciphered is from and what relevance do they have to the maps?	The film that Shannon learns the lyrics from is a French version of "Finding Nemo". She says "the one about the fish" and later sings the song "La Mer" which is known in English as the song "Beyond The Sea" which plays in Finding Nemo's credits
1.13 Hearts and Minds	What is the hatch that Locke and Boone found?	2.01 Man of Science, Man of Faith - It's a entrance/exit to some form of bunker.
1.14 Special	Where has Claire been?	Claire was taken to the Dharma medical station called the Staff.
1.15 Homecoming	What has happened to Claire's memory?	Ethan drugged her extensivley to make her forget.
1.18 Numbers	How is it that the numbers Hurley used when winning the lottery match the numbers Danielle Rousseau had written on her scribblings?
	What is the origin of the numbers?	The numbers end up being the code used to reset the timer in the hatch that controls the magnetic device.
1.19 Deus Ex Machina	How come Locke doesn't feel pain in his legs?	1.22 Born to Run - We find when Walt asks him if his leg injury hurts that it now does. So it appears that his paralysis returned temporarily and after it wore off he began to feel the pain.
	Why did Locke lose the use of his legs again temporarily?
	What was the light that came on in the hatch?	dude,Desmond just turned on the light...
1.24 Exodus: Part 2	How did a ship end up 2 miles inland?
	Who were the dudes who took Walt?	Those dudes were the Others.
	Why do they want Walt?	Walt has special abilities that they want to study.
2.01 Man of Science, Man of Faith	What is the bunker?	2.03 Orientation - Some sort of experimental station created by an organization called the Dharma Initiative. It turns out that there are more than one and they are named, this one is called the Swan.
	What is Desmond doing in the bunker?	2.03 Orientation - Desmond reveals that he was shipwrecked during a round the world race and brought into the bunker by a guy called Kelvin.
2.03 Orientation	Who are the Dharma Initiative?
	What was the 'Incident' referred to in the orientation tape?
	What will happen if the numbers aren't entered into the computer in time?	The first time the magnetic energy harnessed there is let loose and is actually what crashes the plane, the second time Desmond flips the shutoff releasing the energy and destroying the hatch at the same time.