I am confused by the books out there for stochastic calculus. I started with Baxter and then moved on to Shreve-2 for finance. But I am wondering how useful it is to read even more advanced books like karatzas shreve and rogers, williams. It will take a huge amount of time( more than one year) to even understand these books that too with extreme dedication. Is it that useful for any job in Wall Street. I know it is useful for academia.