Short answers, pulled from the story.
The three formal goals of embalming are sanitization, presentation, and preservation. Restoration is an important additional factor in many cases, particularly when a body has been damaged by accident, disease, or the effects of decomposition.
Embalming became widespread in the United States during the American Civil War, when servicemen often died far from home and families wished to have remains returned for local burial. The public embalming and transport of Abraham Lincoln's body after his assassination in 1865 brought the practice to broad national attention.
Modern embalming fluid typically contains formaldehyde, glutaraldehyde, methanol, humectants, wetting agents, and other solvents. The formaldehyde content generally ranges from 5-35% and the methanol content may range from 9-56%.
Dr Frederic Ruysch (1638-1731) is credited as the first to use arterial injection for embalming. His results were so lifelike that observers reportedly thought the preserved bodies were still alive, though he applied the technique solely for preparing anatomical specimens.
Embalming is not mandatory in the United States. It is, however, a general legal requirement for the international repatriation of human remains to the U.S., with some exceptions.
The Thiel method was developed gradually from the 1960s onward by anatomist Walter Thiel at the Graz Anatomy Institute in Austria. It uses 4-chloro-3-methylphenol and various salts for fixation, boric acid for disinfection, and ethylene glycol for tissue plasticity, and uniquely preserves the cadaver's natural color, texture, and flexibility for surgical training and research.