I am looking for a book that is introductory in terms of mathematics, yet does not hesitate to go into detail after a nice introduction, while advanced on the evolutionary aspect. Thank you.
Thank you Robert, I had considered that (as I'm currently reading his one and only: "major transitions of evolution"), but wasn't sure if it is above my level or appropriate.
There is a nice chapter about it in Richard Dawkin's 'Selfish Gene', I'm guessing that you have already read this and you're looking for something a little more advanced?
Maynard Smith's above is solid, it also depends what level you're after.
Mathematician Karl Sigmund had written "Games of Life" back in 1993 , a pretty informative general-level intro to the subject with a biological slant, maybe a bit dated by now however.
I recommend Otto and Day's book "A Biologist's Guide to Mathematical Modeling in Ecology and Evolution". They have a section devoted to ESS modeling with recent examples. http://press.princeton.edu/titles/8458.html
I also suggest "Evolutionary Ecology of Plant Reproductive Strategies" by Klinkhammer and de Jong even if you are not studying plant evolution. They have a very gentle and friendly approach that assumes no prior knowledge. You will find no more basic book if your goal is to get up and running quickly.
I a m not sure what you are looking for, a book on evolutionary game theory or a book on non-cooperative GT that has references to evolutionary biology. If you are looking for the fiormer I would go for Weibull (1995): Evolutionary Game Theory, mit press. In case you are looking for the latter then you could check out Herb Gintis (2000): game theory evolving, Princeton University Press.
You could also try the chapter by Parker in: Behavioural Ecology: an Evolutionary Approach (2nd ed) Krebs, J.R. & Davies N.B., eds. pp 30–61 as an excellent brief, yet in depth treatment of this subject.
...and an afterthought after my previous answer: what would also be interesting read is part III of the book by Mangel and Clark: dynamic modelling in behavioural ecology. This is a slightly different approach to the basic theory of ESS. I hope this will be helpful!
Some of the models for optimizing under constraints came from microeconomics and brought over into evolutionary theory i.e. optimal foraging, optimal clutch size, optimal genetic foraging. You could check in the microeconomic world for games too?