The first 173 pages are organized by country, and within each country the Chiefs of Mission are listed chronologically. Of these, NameBase picked up the entries starting around 1946. In addition to the name and the dates when they were appointed, assumed office, and left office, their home state and official title are included. A 25-page appendix, which we skipped, lists alphabetically all the names in the prior section. This second list usually includes full middle names (instead of just an initial), as well as the year of birth and death. Additional information would also be available from appropriate editions of Who's Who in America, which makes a point of including ambassadors.
Compile a name index for this source
Search the NameBase site: While the best way to search for names is to use NameBase, most can also be found here by using only first and last name, separated by a single space, with no quotation marks.