The Wall Street Journal has published a short article commemorating the book in which psychologist Howard Gardner announced his theory of the “multiple intelligences”: Frames of Mind (1983). [I'd recommend starting with Gardner's 2000 sequel: Intelligence Reframed].
This WSJ article is light-hearted, though it makes some serious points along the way. It reads as though the writer had an epiphany when he finally realized that multiple intelligence theory does not hold that every child is a genius. Gardner’s theory doesn’t hold that all children are equally capable. Rather, MI theory holds that there are many ways to measure intelligence (at least nine major ways, according to Gardner) and that these multiple intelligences don’t meaningfully meld into any sort of all-purpose single score. Gardner’s main point is that the traditional alleged all-purpose intelligence rating (think of the score of an old-fashioned IQ test) that many educators have traditionally labelled general intelligence is a real world fiction that stigmatizes many children who are brilliant in many ways that society values highly, though they might not excel at math or reading.
In sum, there are a variety of ways in which children (and adults) excel or flounder, and we are better off recognizing a reality-based multi-scale spectrum rather than jamming all of our children under a single scale that measures only few of the well-substantiated intelligences recognized by Gardner:
[Gardner] noted that, while some parents might recoil from an intelligence theory that brings so many into the fold, others might dislike that it opens up new vistas in which their children prove to be below average. I hadn’t thought about that. Contrary to popular misperception, Mr. Gardner explained, MI [multiple intelligence] theory doesn’t mean that every child is outstanding at something. Some children can be below average at everything. My heart sank. . . Alas, here was the kindly Harvard psychology professor hinting that, while there are more avenues to genius, there are also more opportunities to prove oneself stupid.
[Note: There is an excellent grade school in my city (St. Louis, Missouri) that utilizes a curriculum based on Howard Gardner's multiple intelligence theory: New City School. ]