A Spectrum of Criticism from the Most Biographical to the Most Formal

Of the Sonnets we do not well know what to say. The subject of them seems to be somewhat equivocal; but many of them are beautiful in themselves, and interesting as they relate to the state of the personal feelings of the author ...
William Hazlitt (1817)

With this key Shakespeare unlocked his heart
William Wordsworth (1827)

Did Shakespeare? If so, the less Shakespeare he!
Robert Browning (by way of reply) 1876

He is a bold man who sets out in quest of the key which shall unlock the mystery of Shakespeare’s sonnets... The belief that the sonnets contain the clue which leads straight into the hidden penetralia of Shakespeare’s biography is at the root of most of the investigation that has been spent on them.
Lytton Strachey (1905)

At a first glance a far larger proportion of Shakespeare’s sonnets give the reader the illusion of personal confessions than those of any contemporary, but when allowance has been made for the current conventions of Elizabethan sonnetteering, as well as for Shakespeare’s unapproached affluence in dramatic instinct and invention - an affluence which enabled him to identify himself with every phase of human emotion - the autobiographic element, although it may not be dismissed altogether, is seen to shrink to slender proportions.
Sir Sydney Lee (1916)

... Shakespeare’s sonnets engage the reader’s interest in a manner akin to the dramatic. Sonnet 89 is presented as a ‘still’ from a love-drama ...
G K Hunter (1953)

The Sonnets can be interpreted as a drama. They have action and heroes. The action consists of lyrical sequences which slowly mount to a tragedy. There are three characters: a man, a youth and a woman. This trio exhaust every form of love and go through all its stages...
The fourth character of the drama is time. Time which destroys and devours everything.
Jan Kott (1964)

I begin with a most obvious feature: generally they are ill constructed.
John Crowe Ransom (1938)

The Shakespearean sonnet is not an easy form to handle. ... the final couplet of the English sonnet is too brief to contain the entire counter-statement to the first three quatrains without giving the impression that the poet is trying to wrench the popem back on its course.
M M Mahood (1957)