Perturbation Theory Help!! Hello physicsforums.com, The last two weeks of my nuclear engineering course covered a mathematical topic known as 'perturbation theory'. It was offered as a 'method to solve anything' with; the problem is, however, that nobody in my class understands it. Basic google searching has not yielded any great results, so I turn to the wise physicsforums.com community to perhaps help give new perspective or recommend some relatively easy to follow readings. Thanks in advance!