What are examples of well received mathematical papers in which the author provides detail on how a surprising solution to a problem has been found. 


I am especially looking for papers that also document the dead ends of investigation, i.e. ideas that seemed promising but lead nowhere, and where the motivation and inspiration that lead to the right ideas came from. 


By "surprising solution" I mean solutions that feel right at first reading and it isn't clear why they haven't been found earlier. 



Examples of Mathematical Papers that Contain a Kind of Research Report
Richard P. Stanley's [How the Upper Bound Conjecture was proved](http://www-math.mit.edu/~rstan/papers/ubc.pdf) ends with two morals:



> 
> 1. The shortest path may not be the best.
> 2. Even if you don’t arrive at your destination, the journey can still be
>  worthwhile.
> 
> 
> 


