The title song was actually the theme song from the television show "Route 66," composed by Nelson Riddle, with a lyric added by Stanley Stein, son of Jule Styne. Thornton's version, which used the same arrangement as Riddle's own instrumental version (a huge hit,) got a bit of radio play when it first came out, but nowhere near as much as the instrumental. I don't recall ever hearing any of Thornton's other recordings on the radio, and I often wondered what had become of her.
According to the Internets, great solver of mysteries, there were problems with drugs and drink and abusive relationships, and she ended up singing in bars for decades. But the Internets also reveal that she had a strange side career as a session singer for recordings of what have come to be called song-poems, most of these in association with Rodd Keith (aka Rod Rogers, Rodney Eskelin,) a composer and musician who made a career of setting to music and recording the verses written and sent in by amateur and aspiring song writers who paid for the service— the recording industry's equivalent of a vanity press (yes, I know this sentence is too long and convoluted, but I don't feel like fixing it.) I'm not sure how long this phase of Thornton's career lasted, but it seems to have gone on for several years after 1964.
The few songs at YouTube are a mixed bag. Most of the tracks uploaded from her early albums are cursed by the sort of odd arrangements that were the bane of popular music during the period, but there is one standout; a peculiar, latinesque jazz/R&B-inflected arrangement of the show tune "Heart" from "Damn Yankees." This has never been one of my favorite songs, but Thornton's version, which I had never heard before, I found surprisingly enjoyable.
Also worth a listen is another show tune, "I Believe In You," from "How to Succeed in Business Without Really Trying." This track is from her 1999 album "I'll be Easy to Find," and she is backed by the classic jazz trio of piano, bass, and drums. Her voice hadn't lost its power during her long hiatus from recording. It's an indication of what an enjoyable body of work she might have left had her career been sustained for forty years.
As an interesting addition, here is "Somebody Else," one of the song-poems she recorded (under the pseudonym Teri Summers) with Rodd Keith, probably only moments after first seeing the chart (that's the way that industry operated.) This is the only one of her song-poem recordings I've been able to find on YouTube. It's difficult to Google for her pseudonym because there is a famous porn star who uses the name Terri Summers, and search results are invariably clogged with links to (I imagine) pictures of her naughty bits. The Internets giveth, and the Internets often giveth too much.
It was a very nice day today, warm and sunny, and the sky was decorated with bits of cloud fluff. Tomorrow will probably be just as nice, so it will be a pleasant time to sit outside waiting to watch my Christian neighbors get raptured. After they're gone, I intend to rifle through their stuff. What!? Hey, I deserve to get something out of the apocalypse, too!