IDA - (Interactive Disassembler)
Witten by Ilfak Guilfanov, is a commercial program used for disassembling a wide selection of file types supporting the architectures of over 30 microprocessors.
Supports many binary file formats.
When it comes to reverse engineering a binary or library file, IDA is the most advanced tool available.
IDA has seen widespread use by intelligence agencies, security analysts, hackers as well as by Fortune 500 companies.
Upon Disassembler, it's has some of the characteristics of a decompiler - recognizing the code pattern of a particular functions in most compilers.
It has a internal scripting language (IDC), which automate some of disassembling procedures.