This book is serious in content and rigorous in approach, yet humorous and light-hearted in style. Prof. Nowak shows how important it is for biologists to have a command of mathematics -- or, actually, more than just a command of it. He shows how many topics of present-day biology can only be analyzed, pursued and researched by using a range of mathematical techniques. Many topics are covered, some of which are from the range in which Prof. Nowak has published ground-breaking research papers.
Make no mistake: this is not one of the "popularizations" that attempt to explain or elaborate on the necessity of mathematics in biology but do so "without any math..." implying that one can use words to portray the mathematics. The book does not, however, present intricate formalism(s) and detailed proofs, etc. This latter part is both its strength and its drawback: in order to avoid long proofs, clarifications, examples, etc., Prof. Nowak simply states results (and some are certainly not intuitively obvious), thereby, alas, leaving the careful reader in a quandary: "where did he get that from?" I suggest that referencing of the pertinent literature (where a more elaborate presentation can be found! not the original, technical publications!) would help many readers who really want to use mathematics in order to pursue biology.
I myself am a biomathematician, and I praise/envy Prof. Nowak's style and his breathtaking clarity; his ability to summarize an exact result in a few lines after perhaps one or two paragraphs introducing the topic. When comparing the wordiness of some non-mathematical biologists (Stephen Jay Gould, for example) with his presentation of the same logical structure of biology, it becomes clear why much wordiness in biology is apparently due to lack of mathematics expertise. Take, as a simple example, one presentation by Prof. Nowak: why a simple, straightforward mathematical proof (by Jenkins) shows that Charles Darwin's view of mixed heredity cannot lead to selection (as genetic variance disappears). All the heavy, wordy tomes that have been written without seriously considering the implications of this "obvious" feature for evolution become lightweight in content.
Incidentally, one is inclined to more than smile at Prof. Nowak's quoting Charles Darwin (the one of Beagle fame) as having said he (Darwin) would have liked to have had a better "grasp" of mathematics. Why he said this I do not know, but I concur with Darwin, and by implication, with Prof. Nowak.
I would want all biologists, particularly those involved in population ecology, in evolution, in game theory, as well as those those studying predation, selection mechanisms, genetics, traits, etc. to read and understand this book.