Azazel is a character created by Asimov and featured in the series. Azazel is a two-centimeter-tall demon (or extraterrestrial), named after the Biblical demon.
Some of these stories were collected in Azazel, first published in 1988. The stories take the form of conversations between an unnamed writer (whom Asimov identifies in the collection introduction as himself) and a shiftless friend named George (named in “The Two-Centimeter Demon” as George Bitternut).
At these meetings, George tells how he is able to conjure up Azazel and their adventures together.
George’s greatest goal in life is a free lunch (or dinner, or ride, etc.), but Azazel is constrained so that he cannot directly benefit George.
George can only call upon Azazel for favors to various friends, which invariably go awry. The stories’ theme about a demon or alien that grants wish echoes an earlier work by Lester del Rey, titled “No Strings Attached” from 1954.
“Getting Even” (1980) was the first story featuring Azazel, and was also the first “Union Club Mystery”.
Asimov stated that this story was omitted from both “The Union Club Mysteries” (1983) and the Azazel collection because it did not match the later stories in either series. However, it does appear in another anthology, “Tales from the Spaceport Bar”.
“Perfectly Formal” (1991) was a story within a story, purportedly written by a robot called Cal. It appeared in a story (also called “Cal”) about a robot who learns how to write stories. “Cal” appeared in the collection “Gold”.
Asimov was a highly successful and prolific writer of science fiction and of science books for the layperson. He wrote or edited about 500 volumes, of which the most famous are those in the Foundation and robot series.
Source:Tehran Times