Titus Coan (1835–81), a New England–trained educator and physician, used his knowledge of both fields to work as a missionary on the island of Hawaii, long before the island became part of the United States. Coan faced a crossroads where he could commit his life to one of several respectable and financially secure professions, but he decided to pack up his life and move to an unknown land to share the gospel. A quick survey of his life can be found here, and his entire autobiography can be found here. Coan made this choice to take the gospel to Hawaii as a young man. He and his wife left all they knew to answer Jesus’s call. Interestingly, because Coan was such a detailed and scientifically minded person, he documented geographical changes he noticed on the island. His notes are still respected by scientists who study the geography of the island. (Examples can be observed at https://evols.library.manoa.hawaii.edu/handle/10524/170.)