Reddit mentions of An Introduction to the Mathematics of Financial Derivatives

Depends on what you're interested in -

Most of my work is in derivatives so would recommend

• Dynamic Hedging - Nassim Taleb
  
• Options, Futures and Other Derivatives - John C. Hull
  
  Those are good starter books and far, far beyond what you'll get out of all three levels of the CFA. There are much more mathematically focused books out there as well.
  
  If you want to get mathy -
  
  
• An Introduction to the Mathematics of Financial Derivatives - Neftci
  
  This was my first serious finance book in undergrad and I still reference it today.
  
  
• Corporate Finance - Ross, Westerfield, Jaffe
  
  Fixed Income
  
  
• Fixed Income Investing - Fabozzi
  
  I'm probably least strong in the equity space but most people recommend this book (I haven't read it)
  
  
• Securities Analysis - Graham, Dodd