Didone (/diˈdoʊni/) is a genre of serif typeface that emerged in the late 18th century and was the standard style of general-purpose printing during the 19th century. It is characterized by:

The term "Didone" is a 1954 coinage, part of the Vox-ATypI classification system. It amalgamates the surnames of the famous typefounders Firmin Didot and Giambattista Bodoni, whose efforts defined the style around the beginning of the nineteenth century. The category was known in the period of its greatest popularity as modern or modern face, in contrast to "old-style" or "old-face" designs, which date to the Renaissance period.

Didone types were developed by printers including Firmin Didot, Giambattista Bodoni and Justus Erich Walbaum, whose eponymous typefaces, Bodoni, Didot, and Walbaum, remain in use today. Their goals were to create more elegant designs of printed text, developing the work of John Baskerville in Birmingham and Fournier in France towards a more extreme, precise design with intense precision and contrast, that could show off the increasingly refined printing and paper-making technologies of the period. (Lettering along these lines was already popular with calligraphers and copperplate engravers, but much printing in western Europe up to the end of the eighteenth century used typefaces designed in the sixteenth century or relatively similar, conservative designs.) These trends were also accompanied by changes to page layout conventions and the abolition of the long s. Typefounder Talbot Baines Reed, speaking in 1890 called the new style of the early nineteenth century "trim, sleek, gentlemanly, somewhat dazzling". Their designs were popular, aided by the striking quality of Bodoni's printing, and were widely imitated.

In Britain and America, the lasting influence of Baskerville led to the creation of types such as the Bell, Bulmer and Scotch Roman designs, in the same spirit as Didone fonts from the continent but less geometric; these like Baskerville's type are often called transitional serif designs. Later developments of the latter class have been called Scotch Modern and show increasing Didone influence.

Didone typefaces came to dominate printing by the middle of the nineteenth century, although some "old style" faces continued to be sold and new ones developed by typefounders. From around the 1840s onwards, interest began to develop among artisanal printers in the typefaces of the past.

Many historians of printing have been critical of the later Didone faces popular in general-purpose printing of the nineteenth century, especially following the reaction of the twentieth century against Victorian styles of art and design. Nicolete Gray has described later Didone typefaces as depressing and unpleasant to read: "the first modern faces designed around 1800 and 1810 are charming; neat, rational and witty. But from that time onwards nineteenth-century book types grow more and more depressing; the serifs grow longer, the ascenders and descenders grow longer, the letters crowd together; the normal mid nineteenth-century book is typographically dreary. The Victorians lost the idea of good type to read." Historian G. Willem Ovink has described late nineteenth-century Didone types as "the most lifeless, regular types ever seen". Stanley Morison of the printing equipment company Monotype, a leading supporter of the revival of "old-style" and transitional typefaces, wrote in 1937 of the eighteen-fifties being a time of "batteries of bold, bad faces" and said that "the types cut between 1810 and 1850 represent the worst that have ever been."

Driven by the increasing popularity of advertising, whether printed or custom lettering, the beginning of the nineteenth century saw the development of bold lettering and the arrival of types of letterform that were not simply larger versions of body text faces. These included the sans-serif, slab-serif and new styles of bold blackletter, but also Didone-style letters that emboldened or decorated the roman type form. Known as 'fat faces', these showed magnified contrast, keeping the thin parts of the letter slender while magnifying the vertical strokes massively. Other "effect" typefaces were sold such as patterned letterforms which added a pattern to the bold parts of the fat face letter, and the pre-existing inline types with a line inside the type.

Didone fonts began to decline in popularity for general use, especially in the English-speaking world, around the end of the nineteenth century^{[citation needed]}. The rise of the slab serif and sans-serif genres displaced fat faces from much display use, while the revival of interest in "old-style" designs reduced its use in body text. This trend, influenced by the Arts and Crafts movement and antiquarian-minded printers such as William Morris, rejected austere, classical designs of type, ultimately in favour of gentler designs. Some of these were revivals of typefaces from between the Renaissance and the late eighteenth century such as revivals (with varying levels of faithfulness to the originals) of the work of Nicolas Jenson, William Caslon's "Caslon" typefaces and others such as Bembo and Garamond. Others such as "Old Styles" from Miller and Richard, Goudy Old Style and Imprint were new designs on the same pattern.