As the news hits this morning of Bernie Madoff's death, I'm reflecting on my unique experience directly communicating with him from prison over the last few years of his life. Here's some of the biggest insights I gained about his scheme, his psyche, and more: 1/ While writing my book, Madoff and I exchanged over 400 pages of handwritten letters and emails between us. In these interviews and others with his family, I gleaned more on how the extensive fraud worked, how he hid it for so long, and even why and when the scheme started. 2/