Megillat Esther is read on Purim from a handwritten parchment scroll. It is better to read from a scroll, but ok to read it from a book if a scroll is unavailable.
Traditionally, trainee sofrim, scribes, cut their teeth by first writing a Megillat Esther. Esther is known as the "easiest" biblical book to write (though there's nothing easy about being a scribe). Unusually, Esther does not contain the name of God and writing the Holy Name requires scribes to concentrate with special purity of intention.
Some argue that the halachah allows women also to write a Megillat Esther. The arguments are involved but perhaps the strongest is that the megillah itself tells us that Esther herself wrote the first megillah scroll: "Then Esther the queen, the daughter of Avihayil, and Mordechai the Jew, wrote with all emphasis to confirm this second letter of Purim" ( 9:29). Women's megillah readings have become accepted in Britain; one or two groups of Orthodox women in the US have written megillot.