Everything you wanted to know, except how to get it. Worth every penny you paid for it.
For a quick-and-dirty summary of my views of happiness and well-being, see: What is happiness?
For a more extensive survey of research on happiness, see my Stanford Encyclopedia of Philosophy entry on happiness. See also the related entry on well-being. An accessible discussion appears in my book, Happiness: A Very Short Introduction (Oxford University Press 2013).