A

A ship captain is a good man to marry if it is a marriage of love, for absences are a good influence in love, and keep it bright and delicate; but he is just the worst man if the feeling is more pedestrian, as habit is too frequently torn open and the solder has never time to set.

Robert Louis Stevenson, Virginibus Puerisque

a is also for agatha, apple, alice, apache, again, augment, antelope, awesome, australia, antarctica, astronomy, alligator, association, antipathy, anger, addled, aggregation, assonance, alimentary, antiquated, annoyed, allaphone, aphrodisiac, alumni, almighty, afraid, afford, afro, animosity, allegiance, android, androgeny, arithmetic, amorous, adored, aproached, allibrandi, ameoba, accustom, antedote, anticipate, appear, aubergine, accidental, affluent, agog, adhere, accordian, ad infinitum

a is also for agatha, apple, alice, apache, again, augment, antelope, awesome, australia, antarctica, astronomy, alligator, association, antipathy, anger, addled, aggregation, assonance, alimentary, antiquated, annoyed, allaphone, aphrodisiac, alumni, almighty, afraid, afford, afro, animosity, allegiance, android, androgeny, arithmetic, amorous, adored, aproached, allibrandi, ameoba, accustom, antedote, anticipate, appear, aubergine, accidental, affluent, agog, adhere, accordian, ad infinitum

i find a very useful when referring to the nonspecific, but when you have a particular to mention, there's nothing like the.

A knowledge that another has felt as we have felt, and seen things, even as they are little things, not much otherwise than we have seen them, will continue to the end to be one of life's choicest pleasures.

Robert Louis Stevenson, Roads

To say »a« means to say »b«. It's just the beginning of a long trail. letters line up, break out of line, making sense, or nonsene. An »a« is just the beginning of a story, told by life, truth, consciousness, lie and you.
Don't lose your letters, for you lose your »z« when your »a« is gone.

A is for apple, and, well of course, for »and.«