Electrospray laser desorption ionization (ELDI) combines the features of both electrospray ionization and laser desorption. It allows direct, sensitive, and rapid analyses of chemical compounds on the sample surfaces. Chemical and biological compounds dissolved in polar and nonpolar solvents can also be characterized directly by ELDI-mass spectrometry (MS) through the assistance of fine carbon powders, which absorb the laser energy, suspended in the solution. A new method of ELDI MS, which combines laser desorption with post-ionization by electrospray, was applied to rapid analysis of solid materials under ambient conditions. Ambient molecular imaging by ELDI/MS of dry fungus surface was set up by M. Z. Huang et al. Bovine cytochrome c and an illicit drug containing methaqualone were chosen to demonstrate the applicability of ELDI to the analysis of proteins and synthetic organic compounds. A novel technology—ELDI-MS—for the rapid and sensitive detection of the major proteins that exist in dried biological fluids, bacterial cultures, and tissues under ambient conditions was reported.