Chapter: I have been occupied with this story, during many working hours of two
years. I must have been very ill employed, if I could not leave its
merits and demerits as a whole, to express themselves on its being read
as a whole. But, as it is not unreasonable to suppose that I may have
held its threads with a more continuous attention than anyone else can
have given them during its desultory publication, it is not unreasonable
to ask that the weaving may be looked at in its completed state, and
with the pattern finished.

If I might offer any apology for so exaggerated a fiction as the
Barnacles and the Circumlocution Office, I would seek it in the
common experience of an Englishman, without presuming to mention the
unimportant fact of my having done that violence to good manners, in the
days of a Russian war, and of a Court of Inquiry at Chelsea. If I might
make so bold as to defend that extravagant conception, Mr Merdle, I
would hint that it originated after the Railroad-share epoch, in the
times of a certain Irish bank, and of one or two other equally
laudable enterprises. If I were to plead anything in mitigation of the
preposterous fancy that a bad design will sometimes claim to be a good
and an expressly religious design, it would be the curious coincidence
that it has been brought to its climax in these pages, in the days of
the public examination of late Directors of a Royal British Bank. But,
    I submit myself to suffer judgment to go by default on all these counts,
    if need be, and to accept the assurance (on good authority) that nothing
    like them was ever known in this land.

    Some of my readers may have an interest in being informed whether or no
    any portions of the Marshalsea Prison are yet standing. I did not know,
    myself, until the sixth of this present month, when I went to look. I
    found the outer front courtyard, often mentioned here, metamorphosed
    into a butter shop; and I then almost gave up every brick of the jail
    for lost. Wandering, however, down a certain adjacent 'Angel Court,
    leading to Bermondsey', I came to 'Marshalsea Place:' the houses in
    which I recognised, not only as the great block of the former prison,
    but as preserving the rooms that arose in my mind's-eye when I became
    Little Dorrit's biographer. The smallest boy I ever conversed with,
    carrying the largest baby I ever saw, offered a supernaturally
    intelligent explanation of the locality in its old uses, and was very
    nearly correct. How this young Newton (for such I judge him to be) came
    by his information, I don't know; he was a quarter of a century too
    young to know anything about it of himself. I pointed to the window of
    the room where Little Dorrit was born, and where her father lived so
    long, and asked him what was the name of the lodger who tenanted that
    apartment at present? He said, 'Tom Pythick.' I asked him who was Tom
    Pythick? and he said, 'Joe Pythick's uncle.'

    A little further on, I found the older and smaller wall, which used
    to enclose the pent-up inner prison where nobody was put, except for
    ceremony. But, whosoever goes into Marshalsea Place, turning out of
    Angel Court, leading to Bermondsey, will find his feet on the very
    paving-stones of the extinct Marshalsea jail; will see its narrow yard
    to the right and to the left, very little altered if at all, except that
    the walls were lowered when the place got free; will look upon rooms
    in which the debtors lived; and will stand among the crowding ghosts of
    many miserable years.

    In the Preface to Bleak House I remarked that I had never had so many
    readers. In the Preface to its next successor, Little Dorrit, I have
    still to repeat the same words. Deeply sensible of the affection and
    confidence that have grown up between us, I add to this Preface, as I
    added to that, May we meet again!

    London May 1857

 Dickens basically tells his critics to kiss his rear end. Which, honestly, is business as usual as far as his prefaces are concerned. Dickens declares that he knows what he's talking about, and however viciously he mocks the government or the supermoguls of his time - well, if anything, it's not nearly viciously enough. Oh, and also, the Marshalsea prison doesn't exist anymore.

