Theme: L C - but not a Lost Cause.
17. '70s Wonder Woman portrayer: LYNDA CARTER
23. Wonderland creator: LEWIS CARROLL
36. Borden cow ... and a phonetic hint to this puzzle's four longest answers: ELSIE
44. Her fashion company made the Fortune 500 in 1986: LIZ CLAIBORNE
55. "Who's on First?" funny guy: LOU COSTELLO
Argyle here. Joe Schewe hasn't been here since that punny Sunday in 2016. There are several subtle connections between some clues.
Across:
1. Gumbo pod: OKRA
5. Built with, as straw, sticks or bricks: MADE OF
11. Sculler's need: OAR
14. Indian bread: NAAN. Now a crossword staple.
15. On the train: ABOARD
16. Sport-__: versatile vehicle: UTE
19. Dreidel, essentially: TOP
20. Thus far: YET
21. Bulletin board fastener: TACK
22. Not at all serious, as threats: IDLE
27. Bridge support: TRUSS
29. Rime: HOAR
30. Source, as of knowledge: FOUNT
31. Plane arrivals: LANDINGS
35. Plane measure: AREA. Different plane.
38. Joint malady: GOUT
39. Said again: RESTATED
41. Longtime P&G soap "for women": CAMAY
42. "Who __ blame?": IS TO. "Not moi!"
43. Purvey provisions for a party: CATER
49. Gabor and PerĂ³n: EVAs
50. Hubbubs: ADOs
51. Treat like a dog?: PET. Aah.
54. Luau serving: POI
59. Drop the ball: ERR
60. Accumulate on a surface: ADSORB. [to gather (a gas, liquid, or dissolved substance) on a surface in a condensed layer] Antonym of absorb?
61. Like a busybody: NOSY
62. Ham on __: RYE
63. Itty-bitty: TEENSY
64. Henna and others: DYEs
Down:
1. "For Your Eyes __": Bond film: ONLY
2. Multi-talented Danny: KAYE. From White Christmas (1954).
3. Go ballistic: RANT
4. "Furthermore ... ": "AND ... " (more rant)
5. Colorful parrots: MACAWS
6. Old calculators: ABACI
7. Nerds: DORKS. Originally as a slang term for “penis”, I'm surprised to see it here.
8. Break bread: EAT
9. Metal-bearing rock: ORE
10. New Deal pres.: FDR. (Franklin Delano Roosevelt)
11. One-up: OUTDO
12. Wake Island or Bikini: ATOLL
13. Fend off: REPEL
18. '50s nuclear experiment: A TEST
22. Provide water to artificially: IRRIGATE. The "to" should be dropped from the clue.
23. Maniacs: LUNATICS
24. Indian spiced tea: CHAI
25. Top-rated: A ONE
26. "Cool!": "RAD!"
27. Ripped up: TORE
28. Bitterly regrets: RUEs
30. Partner of wide: FAR
31. '60s hallucinogen: LSD
32. Alaskan city on the Seward Peninsula: NOME
33. __ gum: thickening agent: GUAR. Not AGAR for a change. Wiki
34. Pigs' digs: STY
36. Soulful James: ETTA
37. First of 13 popes: LEO I
40. Comm. system with hand motions: ASL. (American Sign Language)
41. Art able to: CANST. Archaic.
43. Singer with Stills, Nash and Young: CROSBY. David.
44. Sufferer healed by Jesus: LEPER
45. Old piano key material: IVORY
46. Former name of the Congo: ZAIRE
47. Breakfast strips: BACON
48. Smells: ODORS. But bacon frying is an aroma.
51. Clever tactic: PLOY
52. "If all __ fails ... ": ELSE
53. Santa's sackful: TOYS
55. Back muscle, for short: LAT. (Latissimi dorsi)
56. Keats creation: ODE
57. Waste not: USE
58. Tackle's neighbor on the line: END. And our end, too.
Argyle