I made a post in /r/Stoicism a while ago when someone asked about books for Epicureanism. I'll just repost it here (maybe we could make a reading list for the sidebar?):
The influences of Epicurus spread through much of the writings of other philosophers and major historical figures. Prominent examples include Isaac Newton, Karl Marx, and Thomas Jefferson. In fact, the pursuit of happiness part from Jefferson's Life, Liberty, and the pursuit of happiness was likely heavily influenced by Epicurus.
Because Epicureanism fell out of favour for so much of history there are many Epicurean terms which either have not become common parlance or whose meaning is not immediately apparent. Even the term Epicurean itself has been distorted. Here is a list of some of the more useful terms which appear in Epicurean studies. Feel free to add more in the comments. Hope all is well.
Aponia – An absence of pain. For Epicurus pleasure was maximised when you no longer experienced any pain.
Ataraxia – A state of profound tranquillity. Ataraxia is achieved when you have no more worries or fears at all.
Apatheia – The Stoic analogue of Ataraxia. Apatheia is the state of mind achieved when the passions are controlled, perhaps even entirely removed.
Clinamen- This is the term given by Lucretius which describes the random motion of atoms in a void. In the atomic theory of t