Temporarily increase line spacing

How do I temporarily increase line spacing? I have some text on my title page:

\begin{center}
{ \Large \textbf{The Great Thesis About Some Very Great Things Indeed With
a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So} }
\end{center}


I'm finding that the line spacing here is too small, but it's fine elsewhere in the document. How can I make the spacing bigger for just this piece of text?

-

Simply end the paragraph before closing the group associated to \Large so the corresponding \baselineskip will be applied; you can do this by adding \par:

\documentclass{article}

\begin{document}

\begin{center}
\Large\textbf{The Great Thesis About Some Very Great Things Indeed With
a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So}
\end{center}

\begin{center}
\Large\textbf{The Great Thesis About Some Very Great Things Indeed With
a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So}\par
\end{center}

\end{document}


Here's a comparison of both results:

I removed the outer braces since they are not necessary, as the center environment already forms a group.

If you want to have more control over the spacing, you could use the second argument of \fontsize (the first argument gives the font size); a little example:

\documentclass{article}

\begin{document}

\begin{center}
\fontsize{15pt}{15pt}\selectfont\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\begin{center}
\fontsize{15pt}{18pt}\selectfont\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\begin{center}
\fontsize{15pt}{30pt}\selectfont\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\end{document}


producing now:

Another option, not requiring you to explicitly know the font size, is to change the factor in the mandatory argument of \linespread:

\documentclass{article}

\begin{document}

\begin{center}
\linespread{1}\Large\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\begin{center}
\linespread{0.8}\Large\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\begin{center}
\linespread{2}\Large\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\end{document}


Yet another option is a redefinition of \baselinestretch; the following code will produce the same result illustrated just above:

\documentclass{article}

\begin{document}

\begin{center}
\renewcommand\baselinestretch{1}\Large\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\begin{center}
\renewcommand\baselinestretch{0.8}\Large\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\begin{center}
\renewcommand\baselinestretch{2}\Large\bfseries The Great Thesis About Some Very Great Things Indeed With a Pretty Long Title That Will Probably Be Split Between at Least Two Lines
Or So
\end{center}

\end{document}


Finally, there's the setspace package which offers you a series of commands and environments to change "in a sensible way" the value of \baselineskip.

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You can also use setspace package that provides \singlespacing, \onehalfspacing and \doublespacing commands. – Harish Kumar Mar 21 '12 at 0:05
@HarishKumar: yes; I've added the package also to my answer. Thank you. – Gonzalo Medina Mar 21 '12 at 0:51
Very nice of you. Thanks. – Harish Kumar Mar 21 '12 at 0:59
Regarding setspace, be careful with this! Just by including the package (without using any commands of it), it destroyed the layout for me in some places. – neo May 27 '13 at 10:59
One more note which caused me 10 min googling: If \linespread{..} is used without changing font size/style afterwards, then a \selectfont must follow. – neo May 27 '13 at 11:15

that text is set with normal linespacing with a large font, you need to ensure the end of the pargraph is in the scope of the size change. Remove the brace at the start and end of the environment.

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Unfortunately, that makes it a tad too big. How can I just customize the spacing to my needs in this particular place? – Enchilada Mar 20 '12 at 21:11
The other answer has since been edited to cover that case. – David Carlisle Mar 20 '12 at 22:05