This is an introductory textbook on mathematical ecology bridging the subdisciplines of population ecology and ecosystem ecology. The expected reader is you: a beginning graduate student, advanced undergraduate student, or someone who thinks of themselves as a student all their lives, with a working knowledge of basic calculus and basic ecology. While this is intended as a stand-alone text, the level is such that once you have read through it, you will be able to read more advanced texts and monographs such as Ågren and Bosatta (1998) and Kot (2001) with greater depth. While there are other very good introductory texts in mathematical ecology (., Edelstein-Keshet 1988 [reissued.