Stephen Withall should be congratulated for slugging through about 300 pages of examples of requirements. Many of them are quite good. For that alone, I recommend the book for all those who want to know what a fairly well written requirement might look like. If you want to know what a very well written requirement looks like, then you should go attempt to read Tom Gilb's book Competitive Engineering. I say attempt because Gilb is not an easy read.
Withall is honest from the beginning in that this is a book of examples using a pattern language. I don't have much enthusiasm for pattern languages, they seem to confuse me, but that is probably a personal problem. There is little to explain what requirements are or how to get them. This book focus is on writing them down. He does have a really brief (very, very brief) intro to requirements with more promised on the web. I didn't read the web stuff.
What I did learn, and colored my whole perception of the book, is that the working definition of requirement is focused flat on functional requirements. Yes, there is a nod to not functional requirements but they get a short shift throughout the book. Frankly, functional requirements are not that interesting. Yes, they are needed but they are typically really easy to get. It is the not functional requirements that get teams into trouble. It isn't that the software doesn't do what you want, it just does it in a way that you hate.
This is clear in the section on User Function requirements where (even if he told us earlier to specify the problem, not the solution) the examples are full of solution. "The system will refresh itself" and "Whenever a sound is played for the purpose of alerting the user, a visual cue shall also be invoked". Why I ask you? That is solution talk.
Now to be a bit more fair, problem and solution is a relative area so, without a clear description of the context, I can't say what those two examples really are, but my money is on solution. A problem UI requirement for the above is more like, "The user will correctly recognize an alert within X seconds 95% of the time" or something like that.
Bottom line, if you want to have a book of lots of examples, not to bad. In those examples are some good questions. But there is much more to do than to write them down.