It’s an older SCI/FI series about a composer who took his sailboat to Belize to compose a new symphony and encounters extraterrestrials. The aliens are looking for a race that can stand the concept of fighting and killing to help them fight a war.
Does anyone know the name of the series and author?
And lord_vykor is correct by the way; the book described is indeed A Call to Arms by Alan Dean Foster, book one of the series The Damned. (And it’s not that much of an “older” series; it was first published in 1991, you young whippersnapper.)