Up until this point quarks and gluons have been treated in basically the same manner as have leptons, with little acknowledgement of the plain fact that quarks and gluons are never directly seen in experiments in the same way as are electrons, protons, and pions. This voluntary blindness has been possible to the extent that we have always considered processes that have the following two important properties:

1. (i) they never involve any strongly interacting particles in the initial state, and

2. (ii) they never involve any specific combinations of strongly-interacting particles in the final state – so-called exclusive processes.

The only reactions involving hadrons that have been contemplated are inclusive ones, i.e. those for which we have summed over all possible combinations of hadrons that could be produced, sometimes subject to some general flavor-conservation rules.

This is obviously a fairly serious handicap, since the vast bulk of the reactions that are seen in experiments involve strongly-interacting particles of one sort or another. In order to be considered a success, the standard model must provide at least a qualitative, but preferably also a quantitative, picture of these processes. The model does indeed provide such a framework. This chapter and Chapter 9 are devoted to outlining to what extent predictions and post-dictions can be made and to what extent they are successful. The goal is to focus here on those calculations that can be made with the minimum of modeling of the unknown dynamics of strongly-coupled physics.