Introduction to Abstract Harmonic Analysis for undergraduate background I'm looking for a good starting book on the subject which only assumes standard undergraduate background.
In particular, I need to gain some confidence working with properties of Haar measures, so I can better understand the spaces $L^{p}(G)$ for a locally compact group $G$.
For some perspective on what I currently know, I can't yet solve this problem:  Verifying Convolution Identities
Something with plenty of exercises would be ideal.

For a historical view, see

Mackey, George W. Harmonic analysis as the exploitation of symmetry—a historical survey. Bull. Amer. Math. Soc. (N.S.) 3 (1980), no. 1, part 1, 543–698.

