Flatland is a satirical novel written by Edwin Abbott in 1884. Abbott used the book as a platform to satirize rigidness and societal hierarchy, with the depiction of a two-dimensional world inhabited by geometric shapes.

The narrator of the book is a square, who resides in a world called Flatland, which is populated by citizens with different shapes, determined by their place in the social hierarchy.

Because the social structure is based on dimensions, the more edges a shape has, the higher the status it has in society. For instance, women in Flatland are mere line segments, since they are one-dimensional beings. Meanwhile, the ruler of Flatland is a figure known as the Circle, the only three-dimensional figure in Flatland and the most powerful.

The book covers Square's discovery of a third dimension, which he initially found difficult to comprehend. He meets a being from Spaceland, who can move in three-dimensions, leading Square to question the limits of his world.

Square's journey also includes his arrest and imprisonment for trying to convince others of the third dimension's existence. His experience in the prison is another commentary on the rigidity of social classes in Flatland.

Flatland is a significant work of the 19th century because it uses satire to tackle societal issues such as rigid class structures, the role of women, and the limits of human perception.

Abbott's novel was a precursor to later works on the understanding of dimensions and geometry in physics, which helped advance scientific knowledge in the field of mathematics.

Flatland is a must-read for anyone interested in math, philosophy, and criticism of social structures.

The first objection is, that a Flatlander, seeing a Line, sees something that must be thick to the eye as well as long to the eye (otherwise it would not be visible, if it had not some thickness); and consequently he ought (it is argued) to acknowledge that his countrymen are not only long and broad, but also (though doubtless in a very slight degree) thick or high. His objection is plausible, and, to Spacelanders, almost irresistible, so that, I confess, when I first heard it, I knew not what to reply. But my poor old friend's answer appears to me completely to meet it.

"I admit," said he - when I mentioned to him this objection - "I admit the truth of your critic's facts, but I deny his conclusions. It is true that we have really in Flatland a Third unrecognized Dimension called 'height,' just as it is also true that you have really in Spaceland a Fourth unrecognized Dimension, called by no name at present, but which I will call 'extra-height'. But we can no more take cognizance of our 'height' then you can of your 'extra-height'. Even I - who have been in Spaceland, and have had the privilege of understanding for twenty-four hours the meaning of 'height' - even I cannot now comprehend it, nor realize it by the sense of sight or by any process of reason; I can but apprehend it by faith.

"The reason is obvious. Dimension implies direction, implies measurement, implies the more and the less.  Now, all our lines are equally and infinitesimally thick (or high, whichever you like); consequently, there is nothing in them to lead our minds to the conception of that Dimension.  No 'delicate micrometer' - as has been suggested by one too hasty Spaceland critic - would in the least avail us; for we should not know what to measure, nor in what direction.  When we see a Line, we see something that is long and bright; brightness, as well as length, is necessary to the existence of a Line; if the brightness vanishes, the Line is extinguished.  Hence, all my Flatland friends - when I talk to them about the unrecognized Dimension which is somehow visible in a Line - say, 'Ah, you mean brightness': and when I reply, 'No, I mean a real Dimension,' they at once retort 'Then measure it, or tell us in what direction it extends'; and this silences me, for I can do neither.  Only yesterday, when the Chief Circle (in other words our High Priest) came to inspect the State Prison and paid me his seventh annual visit, and when for the seventh time he put me the question, 'Was I any better?' I tried to prove to him that he was 'high,' as well as long and broad, although he did not know it. But what was his reply? 'You say I am "high"; measure my "highness" and I will believe you.'  What could I do?  How could I meet his challenge?  I was crushed; and he left the room triumphant.