if you build it

How to build an anthology truly representative of a century of poets/poetry:
  A. Pick your poets first; then select their best and most representative poems.
  B. Ordered by increasing level of difficulty, identify and select:
    1) Primary: Important figures of enduring reputation and influence. Generally speaking, they are already well-represented in other anthologies or critical histories of the century.
    2) Secondary: Though their reputations and influence may have waned considerably over the years, figures who were important during a period of time. They set off a trend / fashion that during a certain time (generally at least a decade) garnered much attention and critical interest.
    3) Comprehensive: (related to #2) Figures who are representative of a school/movement¸ however fleeting was its influence, which is important to filling out the entire picture of the century’s poetry.
    4) Corrective: Figures whose inclusion will help to correct a bias caused by a general lack of publishing opportunities and attention, resulting primarily from ignorance or neglect by the dominant cultural and critical powers.

Footnote: Don't be cheap and beg if you have to, but don't omit someone important (Ginsberg/Plath) due to steep reprint fees. Solicit donations from major organizations like The Poetry Foundation, Academy of American Poets, etc. You only have one chance to get it right.