Reading the Inscription

The full text
The inscription runs around the top of the bell in two parts. According to the NPS it reads:
Proclaim LIBERTY throughout all the Land unto all the Inhabitants thereof Lev. XXV X
By Order of the ASSEMBLY of the Province of PENSYLVANIA for the State House in Philada
"Lev. XXV X" is a reference to the Book of Leviticus, chapter 25, verse 10. "Philada" is an abbreviation of Philadelphia, and the State House is the building now called Independence Hall, for whose bell tower the bell was ordered in 1751.
The words were set for the Pennsylvania Assembly, which had ordered the bell through its Speaker, Isaac Norris, from the Whitechapel Foundry in London, per the NPS.
What the words meant
The bell carried these words for decades before it had its present name. According to the NPS, "The Anti-Slavery Record, an abolitionist publication, first referred to the bell as the Liberty Bell in 1835." The name dates from 1835, not from the events of 1776. The history page covers how the bell became a symbol.
Is "Pensylvania" a mistake?
The word most visitors notice is "PENSYLVANIA", with one "n" in the middle. It is often described as a misspelling, but it was an accepted alternative spelling at the time. Wikipedia notes that Alexander Hamilton used the same form on the signature page of the Constitution in 1787. So the answer to "which word is misspelled" and "which letter is missing" is Pensylvania, missing one "n", in a spelling that was accepted then. The misspelled word page goes into it.
The makers’ mark
The bell also carries the mark of the two Philadelphia craftsmen who recast it after the London original cracked on first use: "Pass and Stow Philada MDCCLIII". MDCCLIII is 1753 in Roman numerals. The first bell had come from the Whitechapel Foundry in London; Pass and Stow melted it down and cast this one, per the NPS.
Where the crack meets the words
The NPS describes the second crack of February 1846 running "from the abbreviation for 'Philadelphia' up through the word 'Liberty'". The inscription is therefore the easiest guide to finding the thin crack, which is less obvious than the wide, filed repair gap. The crack page explains both marks.
The casting visitors can touch
Visitors cannot touch the Liberty Bell itself. Inside the Liberty Bell Center, though, the exhibit has a casting of the inscription that visitors are encouraged to touch, according to the NPS and Visit Philadelphia. It lets the raised lettering be read by hand.
The Liberty Bell Center is at 526 Market Street, free with no tickets and open daily from 9 am to 5 pm, per the Liberty Bell Center page on nps.gov. From the Chestnut Street windows after hours, the bell is seen from a distance.
Reading the inscription on the casting first makes the words easier to pick out on the bell.
Frequently asked questions
What does the Liberty Bell inscription say?
"Proclaim LIBERTY throughout all the Land unto all the Inhabitants thereof Lev. XXV X" and "By Order of the ASSEMBLY of the Province of PENSYLVANIA for the State House in Philada".
What Bible verse is on the Liberty Bell?
Leviticus 25:10, cited on the bell as "Lev. XXV X".
Is Pennsylvania spelled wrong on the Liberty Bell?
It reads "Pensylvania", with one "n", which was an accepted spelling at the time. See the misspelled word page.
Can you touch the inscription?
Not on the bell, but the exhibit has a casting of the inscription that visitors are encouraged to touch, according to the NPS.