[Tex/LaTex] what is the difference between \twocolumn and \documentclass[twocolumn]{book}

two-column

what is the difference between \twocolumn and \documentclass[twocolumn]{book}?
when I use \twocolumn , the line spread seems smaller?(compare with the same document using \documentclass[twocolumn]{book}) why?

Best Answer

If you specify the document class option twocolumn, and if use the book document class, a default font size of 10pt, and paper size of A4 or USLetter, the entire document will be typeset in two-column mode, and also:

  • \sloppy will be in effect,
  • the default value of \parindent will be 1em,
  • \textwidth will be set to either 469pt (USLetter, ca. 6.49") or 452pt (A4paper, ca. 6.25").

(The widths of the margins will depend on whether oneside or twoside is in effect.)

If you do not specify this document class option but issue the instruction \twocolumn, either in the preamble or somewhere in the body of the document, the subsequent material will be typeset in two-column mode (with a page break inserted first, if necessary), but

  • \sloppy will not be in effect by default,
  • the default value of \parindent will be 15pt, and
  • \textwidth will be set to 345pt (ca. 4.77").

Oh, and the distance to the margin block is also affected by the presence or absence of the twocolumn option.

Of course, default page parameters can be overridden, e.g., via the macros and options of the geometry package.

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