Read “Cross-Domain Mapping“, Chapter 2 of Conceptualizing Music by Lawrence M. Zbikowski. [You will need to be on the UCI LAN or accessing it via VPN in order to read this book online.]

Study the following two examples from a past class, regarding linear mapping and linear interpolation. The first one is pretty math-y, but is worth reading carefully so that you understand linear mapping conceptually. The second one gives a few practical (if not super-useful musically) examples of applying linear mapping to convert one range of numbers into another.
1. Linear mapping equation
2. Linear mapping and linear interpolation

In class Anna and Molly will bring instruments for us to experiment with the pitch-detection object sigmund~.

Read the Wikipedia article on pitch tracking. If you want to read more about how pitch detection is accomplished, there’s no shortage of articles online. The page on Pitch Detection Algorithms by Gareth Middleton gives a pretty clear explanation of two algorithms, and you can read Miller Puckette’s description of his fiddle~ object, which was the predecessor of sigmund~, in his article “Real-time audio analysis tools for Pd and MSP” (a .ps PostScript file).