How did Einstein come up with the theory of special relativity based on then current scientific knowledge?

Did he guess or was there some logical technique he used. Did he use the scientific method. I understand that they are just now proving some of his theory with evidence. I am most interested in his thought process. Did he ever describe how he thought up the special relativity?|||Yes Einstein was famous for creating straightforward "thought experiments" or "gedunken experiments". Before Einstein theorized special relativity a scientist named Maxwell proved that electricity and magnetism are actually different formulations of the same force, "sense" this force by electromagnetic radiation (light). Maxwell proved that the speed of light never changed. Einstein considered this a contradiction of modern theory his thought experiment was essentially: If you were on a train and you emitted a beam of light wouldn't the light be moving faster than the accepted "speed of light" to an observer that is stationary since you add the speeds (speed of train+speed of light). You can think of throwing a baseball on a train, to somebody outside on the ground watching you they would see the ball move with the speed of the train PLUS the speed you through the ball. If this was the case with light then you could change the speed of light. This was the contradiction that led Einstein to really think what the constancy of the speed of light meant, and thus special relativity.|||He was impressed with the results of the famous Michelson Morley experiment, it led him to believe that light speed altered time.