Die Memoiren des Lee Myung-bak

For example, it has been widely known that in Lee's time, Seoul and Pyongyang confidentially discussed the possibility of another inter-Korean summit. Indeed, Lee's memoirs confirmed that such contacts indeed took place in 2009, and again, in late 2010. Lee's memoirs reveal that the confidential negotiations ended in nothing because the North Korean side attached a huge price tag for its willingness to have a summit. 

Again, it has long been known that inter-Korean summits are essentially commercial operations, with the South paying the North for a useful photo-op. The first summit cost $450m, while the second summit was also paid for indirectly.