Between Andrew Jackson and J.P. Morgan, the United States went through six major financial panics. They are often left out of the popular crash canon because no single one of them produced the institutional changes that the 1929 crash later did. But they were each, in their time, severe — and the pattern they established (credit boom, opaque institutions, sudden refusal to pay, contagion via the new communication infrastructure of the era) is the same pattern every later crash has run.