The idea that Brian Wilson woke up one day and decided to create Pet Sounds is a bizarrely enduring misconception within the realm of pop music. In reality, the seeds of that transcendental masterpiece were planted long before The Beach Boys ditched their striped shirts and surfer tunes. In fairness to that misconception, no other band – particularly within the pop-rock scene of early 1960s America – made as substantial a leap in their output as…