I am wanting to brush up on my statistics and get a better mechanistic understanding of tests I'm using, and learn new tests and theory, so I have decided to work through Sokal and Rohlf's Biometry, 4th edition. I hope you will find this as helpful as I am sure I am going to find it. I'll do one chapter at a time; or if some turn out to be really long, possibly even break them up further into sections.
To start, with a really short one, Chapter 1 reviews some general terminology (biometry as the measuring of life; hence the book focusing on statistics as applied to biology). Data are plural; a datum is singular! Statistics is the study of "data describing natural variation" by quantifying and comparing populations or groups of individuals. Section 1.2 covers the history of the field and 1.3 discusses "The statistical frame of mind", which justifies why we use statistics. (Short answer: To quantify relationships in terms of probability, allowing us to better understand relationships among variables of interest.)