| Issue | #53 |
| Published | November 1977 |
| Cover Price | 0.35 |
| Pages | 36 |
| Editing | Archie Goodwin |
| Notes | Letters page replies by David Anthony Kraft. |
| Characters | Defenders [Red Guardian [Dr. Tania Belinsky]; Sub-Mariner [Namor]; Hellcat [Patsy Walker]; Nighthawk [Kyle Richmond]; Hulk [Bruce Banner]] |
| Genre | superhero |
| Pencils | George Perez (signed) |
| Inks | Bob Wiacek (signed) |
| Letters | Irving Watanabe |
| Notes | Letters page replies by David Anthony Kraft. |
| Reprinted | In Essential Defenders (Marvel, 2005 series) #3 |
| Characters | Defenders [Red Guardian [Dr. Tania Belinsky]; Sub-Mariner [Namor]; Hellcat [Patsy Walker]; Nighthawk [Kyle Richmond]; Hulk [Bruce Banner]; Valkyrie]; Lord Vashti; Sergei; Clea; Lunatik |
| Synopsis | Defenders travel to Atlantis to determine the source of radiation that is killing the Atlanteans. |
| Genre | superhero |
| Script | David Kraft |
| Pencils | Dave Cockrum (pg 1); Keith Giffen (pp 2,3,10,11,15,17,18); Mike Golden (pp 6,7,14,16) |
| Inks | Terry Austin |
| Colors | Phil Rachelson |
| Letters | Joe Rosen |
| Notes | The Power Principle Part 1. Interior credits confirmed in the letters page to The Defenders #57. |
| Reprinted | In Essential Defenders (Marvel, 2005 series) #3 |
| Characters | Clea; Nicodemus |
| Synopsis | Nicodemus disguises himself as a mugger to get the jump on Clea. |
| Genre | superhero |
| Script | Naomi Basner |
| Pencils | Sandy Plunkett |
| Inks | Tony Salmons |
| Colors | Marie Severin |
| Letters | Joe Rosen |
| Reprinted | In Essential Defenders (Marvel, 2005 series) #3 |