From the recent Selected Poems collection of Walt Whitman's work (edited by Gary Schmidgall), here's a brief excerpt from Whitman's introduction to the 1855 edition of LEAVES OF GRASS:
"The great poets are also to be known by the absence in them of tricks and by the justification of perfect personal candor. Then folks echo a new cheap joy and a divine voice leaping from their brains: How beautiful is candor! All faults may be forgiven of him who has perfect candor. Henceforth let no man of us lie, for we have seen that openness wins the inner and outer world and that there is no single exception...."