How might one summarize the "Dedication" from Lord Byron's Don Juan?

The “Dedication” to Lord Byron’s Don
Juan might be summarized as
follows:

• Byron opens the dedication by mocking
  Robert Southey, as well as William Wordsworth and Samuel Taylor Coleridge, for having
  abandoned their earlier liberal political beliefs (1-16) and for having declined in
  skill as poets (17-64). He suggests that they have been motivated partly by desire to
  win official approval and financial reward.


• He contrasts
  Southey, Wordsworth, and Coleridge with John Milton, the great revolutionary poet of the
  seventeenth century, who remained committed to his original radical political principles
  even when it was disadvantageous to do so (64-88).


• He
  mocks Viscount Castlereagh, an important political figure of the time, whom Byron
  detested (89-128), depicting him as an enemy to freedom
  everywhere.


• He returns to his mockery of Southey
  (129-36), accusing him of political hypocrisy and self-serving
  flattery.

The dedication thus establishes
Byron’s commitment to liberal, lofty political principles as well as to composition of a
kind of poetry that reflects a commitment to those principles and also commitment to
lofty artistic goals we well.  Byron considers Southey (and, to a lesser degree,
Wordsworth and Coleridge) old men who have lost touch with the political ideals and
poetic aspirations that once made them great.  He depicts Southey, in particular (whom
he disliked personally) as a sell-out and
time-server:

readability="16">

Meantime, Sir Laureate, I proceed to
dedicate

In honest, simple verse, this song to
you;

And if in flattering strains I do not
predicate,

’Tis that I still retain my “bluff and blue.”
(129-32)

“Bluff and blue”
were colors associated with the Whigs, the more liberal of the two political parties in
England (Tories being the conservatives).