It's fascinating to read this book just a few years after it was written and to see how things have changed in just that short period of time. It's essentially a snapshot of the state of science at the time, covering 101 open questions in three pages each. One wonders how much of it will need to be rewritten 25 or 50 or 100 years down the line.
The biggest short-term changes are in genetics: Trefil devotes one of his short chapters the Human Genome Project, then well underway and some years from completion. Now, of course, the "first draft" has been completed and geneticists are contemplating the next step. One obsolete fact has come out already: Trefil states that the human genome has about 80,000 genes when the HGP (and the private counterpart Celera) has discovered, surprisingly, that there are only 30,000.
Also, Trefil discusses the possibility of past or present life on Mars without mentioning the controversial Mars meteorite ALH84001, in which, some scientists claim, there are traces of life.
And the last chapter discusses the Y2K problem, then still looming on the horizon, now safely past (thanks to the hard work of many computer programmers, including me).
Other chapters, I think, will be much the same for many years: we still have a long way to go to understand consciousness, to figure out how life began, and to come up with a fundamental theory that covers all of basic physics, both relativity and quantum mechanics. Not surprisingly, all three of these Trefil puts in his "top ten" problems.
All in all, it's a fascinating read and a great bathroom book with its short chapters - for the nerds, at least.