documentclass{book}
usepackage{lipsum}
usepackage{marginnote}
begin{document}
Some text
marginnote{lipsum[1-4]}

end{document}

documentclass{book}
usepackage{lipsum}
usepackage{marginnote}
begin{document}
marginnote{lipsum[1-2]}lipsum[1-5]

end{document}

documentclass{book}
usepackage{lipsum}
usepackage{marginnote}
begin{document}

A wordmarginnote{A margin note} lipsum[1-2]

end{document}