The Many Benefits (sample puzzle from Zen & the Art of Crossword Puzzles by Nikki Katz)

Across 1. Head cover 5. Clay mask 8. Tooth holder 11. Lowest female voice 12. Sprinkler attachment 13. Wide kimono sash 14. Sneer 15. The baby 17. New mother affliction 19. Publicize dirty laundry 20. Study 23. First artificial satellite 27. Faint 29. Actor Affleck 30. Insult 32. Check 33. Wrist accessory 36. Briefcase 39. An Asian peninsula 41. Cool slang 42. Presenile dementia 47. Electric generators 50. Small desktop button 51. Act nosey 52. The Loch __ monster 53. Siamese 54. Sew a folded edge 55. American College of Physicians (abbr.) 56. Arrange Down 1. Placid 2. Margarine 3. Individual unit

4. Layout 5. Make secure 6. Customary 7. Contradicts 8. Brand __ boxer 9. Six pack muscles 10. Mental ability 12. Composite 16. Chew 18. Female passive force 21. Reserve Officers Training Corps (abbr.) 22. Arc builder 23. South by west 24. Reach maximum level 25. Until   26. Sephia manufacturer 28. North by east 31. Afflict 34. Ocean Spray's drink starters 35. A Midsummer Night's Dream lover 37. Thai 38. Acknowledges 40. Ancient Mexican civilization 43. Hospital (abbr.) 44. Reverberate 45. Lion noise 46. Irritation 47. Automobile speed 48. Be 49. Place to exercise

Solution