Solution: The History of Crossword Puzzles
Answer: JOHN GLENN FLIES OUT TO SPACE

Written by Kenny Young

The clues are arranged so that all their answers are in alphabetical order:

#-#. It’s better to not put these on?AIRS
#-#. Unit of hayBALE
#-#. West German capitalBONN
#-#. Matter for a lawyer or detectiveCASE
#-#. “Shucks!”DARN
#-#. Hearing rangeEARSHOT
#-#. Orlando destinationEPCOT
#-#. Type of mattress or pillowFOAM
#-#. Prod to actionGOAD
#-#. Possible precursor? (3 wds.)IF AT ALL
#-#. “Cool me down please!” (3 wds.)I’M SO HOT
#-#. She plays Christine on Star Trek: Strange New WorldsJESS
#-#. Chinese character that looks like a faceJIONG
#-#. Mayor who asked, “How’m I doin’?”KOCH
#-#. French riverLOIRE
#-#. Brief visual inspection (hyph.)LOOK-SEE
#-#. Advanced degree in thermodynamics, e.g.MSME
#-#. Corporal or sergeantNCO
#-#. “Bonne _____!”NUIT
#-#. Dodgeball network, “The ____”OCHO
#-#. French riverOISE
#-#. Cloud of cometsOORT
#-#. Pertaining to sightOPTIC
#-#. Most dogs and cats in the USPETS
#-#. Brad and Janet’s musical film, for shortRHPS
#-#. OceanSEA
#-#. You, of oldTHOU
#-#. Unit of pressureTORR
#-#. Verbal pausesUHS
#-#. Donald Trump’s Generals were involved in thisUSFL
#-#. They deliverUSPS

The instructions say that all entries proceed in a straight horizontal or vertical line from one number (or the “F” and “N” in FUN) to another; this description permits the entries to go backwards as well as forwards. Since “FUN” is locked in place, there is only one way to fill in the rest of the grid:


Image courtesy of https://en.wikipedia.org/wiki/Arthur_Wynne

The final answer, orbiting counterclockwise around the outer edge of the grid, is JOHN GLENN FLIES OUT TO SPACE.