The clever idea of the book is that scientists in 1998, aware that the world is dying from environmental consequences of human activity, send a message back in time in the form of tachyons that interfere with a physics experiment in 1963. Perhaps the most interesting part of it for me was watching the physicist in the past trying to figure out why the interference in his experiment seemed to be a scientific message written in Morse code.

An example of the positive comments about math is this one, from a description of a theory in which one closed universe can be a subset of another:

The mathematical facts that, I must admit, it is nice to see stated correctly in a fictional setting for once, concern Gödel's Theorem and the "fact" that half of the data samples are below the mean. In a casual conversation we hear:

The mention of Gödel (in the context of the possible paradoxes created by the faster-than-light messages) is not what I would refer someone to for a serious description of the theorem, but it is pretty good for a single paragraph in a novel!

What about the cliches? Okay, how about finally figuring out the true nature of the universe right before dying in a plane crash? And, what do you suppose the "butterfly effect" caused by the reception of the message from the future back in 1963 will do? (I hope I'm not surprising anyone with this...) Of course, a kid -- who tells reporters that he was in the book depository to get some magazines with articles about the message from the future -- spots Oswald and tackles him before he kills Kennedy.

The example of racism (there was only one but it is so obnoxious as to seriously affect my opinion of the book) occurs when one character figures out that a nervous looking black man at a bus stop is actually a pick-pocket or mugger and scares him away. He says that if not for the man's skin color he might not have recognized him for what he was! [Note: I have noticed similar racist comments in other Benford writings. There is even another criminal who is recognized because of his "Black-Mexican" origins in his 1979 Calibrations and Exercises, which might qualify as mathematical fiction itself.]

As for the sexism, the scientists in the 1990's (the future when the book was written) are all men with wives who "tend the homefires"...except for one woman scientist who is bi-sexual.