| 0 | - | cover | 1 | pencils: Jack Kirby; inks: Wally Wood | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 1 | Title Page | credits, title page | 1 | pencils: Jack Kirby; inks: Jack Kirby | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan] |
| 2 | Title and Credits | credits, title page | 2 | pencils: Jack Kirby, Bruce Timm; inks: Jack Kirby, Rosalind Kirby, Marvin Stein, Bruce Timm | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley]; ULTIVAC; Jack Kirby |
| 3 | - | credits, title page | 1 | pencils: Jack Kirby, Bruce Timm; inks: Bruce Timm | Jack Kirby |
| 4 | Table of Contents | table of contents | 2 | pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein, Wally Wood | stone giant; June Robbins; Charles Agar |
| 5 | Introduction | foreword, introduction, preface, afterword | 3 | script: Paul Kupperberg; pencils: Jack Kirby | Ace Morgan |
| 6 | - | illustration | 1 | pencils: Bruce Timm; inks: Bruce Timm | Jack Kirby |
| 7 | Showcase #6 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby | Challengers of the Unknown [Ace Morgan; Prof Haley; Red Ryan; Rocky Davis] |
| 8 | The Secrets of the Sorcerer's Box! [Chapter 1] | comic story | 6 | script: Jack Kirby, Joe Simon, Dave Wood; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Ben Oda | Challengers of the Unknown [Ace Morgan; Prof Haley; Red Ryan; Rocky Davis] (introduction for all, origin); un-named sailors; un-named citizens; Mr. Morelian (villain, introduction, death) |
| 9 | Chapter Two: Dragon Seed! | comic story | 6 | script: Jack Kirby, Joe Simon, Dave Wood; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Ben Oda | |
| 10 | Chapter Three: The Freezing Sun! | comic story | 6 | script: Jack Kirby, Joe Simon, Dave Wood; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Ben Oda | |
| 11 | Chapter Four: The Whirling Weaver! | comic story | 6 | script: Jack Kirby, Joe Simon, Dave Wood; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Ben Oda | |
| 12 | Showcase #7 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins; ULTIVAC |
| 13 | ULTIVAC Is Loose! | comic story | 6 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Stan Starkman | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins (first appearance); Felix Hesse (first appearance); ULTIVAC (first appearance) |
| 14 | Chapter Two: A Challenger Must Die! | comic story | 6 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Stan Starkman | Director June Robbins, a computer expert |
| 15 | Chapter Three: The Fearful Millions | comic story | 6 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Stan Starkman | |
| 16 | Chapter Four: The Fatal Prediction! | comic story | 6 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein; letters: Stan Starkman | |
| 17 | Showcase #11 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; General Tolek |
| 18 | The Day the Earth Blew Up | comic story | 7 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; Carl Jackson; Warren Moss; Commander Lockwood; Colonel Price; General Tolek (villain); Garnat (villain); other Tyrans (villains) |
| 19 | Chapter Two: The Tyrans | comic story | 6 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | |
| 20 | Chapter Three: The Thing That Came Out of the Sea | comic story | 6 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | |
| 21 | Chapter Four: One Minute to Doom | comic story | 5 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | |
| 22 | Showcase #12 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby, Roz Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 23 | The Menace of the Ancient Vials! Chapter 1 | comic story | 6 | script: Dave Wood; pencils: Jack Kirby; inks: Leonard Starr; letters: Artie Simek | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Amos Hunter; VILLAINS: Brommer; Gortz; Karnak; Kraken |
| 24 | Chapter Two: The Fire Being! | comic story | 6 | script: Dave Wood; pencils: Jack Kirby; inks: Leonard Starr; letters: Artie Simek | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 25 | Chapter 3: The Demon from the Depths | comic story | 6 | script: Dave Wood; pencils: Jack Kirby; inks: Leonard Starr; letters: Artie Simek | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 26 | Chapter 4: The Deadly Duplicates! | comic story | 6 | script: Dave Wood; pencils: Jack Kirby; inks: Leonard Starr; letters: Artie Simek | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 27 | Challengers of the Unknown #1 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 28 | - | foreword, introduction, preface, afterword | 1 | pencils: Jack Kirby; inks: Marvin Stein | Challengers of the Unknown |
| 29 | The Man Who Tampered with Infinity | comic story | 14 | script: Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins (called June Walker); Olan Tagorian |
| 30 | The Human Pets | comic story | 10 | script: Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 31 | Challengers of the Unknown #2 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 32 | The Traitorous Challenger | comic story | 10 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins (called June Walker); Digger Bill; An atomic beast |
| 33 | The Monster Maker | comic story | 14 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Dr. Hascomb; Roc |
| 34 | Challengers of the Unknown #3 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby, Roz Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins |
| 35 | The Secret of the Sorcerer's Mirror | comic story | 12 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Kregon the Sorcerer; a genie; Hillary Mycroft; Mycroft's gang |
| 36 | The Menace of the Invincible Challenger | comic story | 12 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Marvin Stein; letters: Pat Gordon | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; June Robbins (called June Walker); Professor Curtis; Chopper; Roxie |
| 37 | Challengers of the Unknown #4 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; Darius Tiko |
| 38 | The Wizard of Time, Chapter 1 | comic story | 5.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; Professor Harlan Fuller; Darius Tiko |
| 39 | Chapter II: The Men Who Rode Across the Sun | comic story | 4.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; an oracle |
| 40 | Chapter III: The Sorcerer's Sect | comic story | 6.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; Rhamis |
| 41 | Chapter IV: The Mechanical Judge | comic story | 6.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; Darius Tiko; The United Earth Police |
| 42 | Challengers of the Unknown #5 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; June Robbins; Vreedl |
| 43 | The Riddle of the Star-Stone, Chapter One | comic story | 7.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Wally Wood | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; June Robbins; Professor Brandon; Vreedl |
| 44 | Chapter Two: The Birdman of Djiizari! | comic story | 7.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Wally Wood | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; June Robbins; Vreedl |
| 45 | Chapter Three: The Challenge of the Super Creature! | comic story | 8.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Wally Wood | Challengers of the Unknown [Ace Morgan; Rocky Davis; Professor Haley; Red Ryan]; June Robbins; Vreedl |
| 46 | Challengers of the Unknown #6 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins |
| 47 | Captives of the Space Circus | comic story | 14.67 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: John Duffy | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; captive aliens; Tartan the Ringmaster; the Stupendous Interplanetary Circus |
| 48 | The Sorceress of Forbidden Valley | comic story | 9.67 | script: Ed Herron, Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Ray Holloway | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins; Charles Agar; the Shong; residents of Forbidden Valley |
| 49 | Challengers of the Unknown #7 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Jack Kirby; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis] |
| 50 | The Beasts from Planet 9 | comic story | 12.67 | script: Jack Kirby, Ed Herron; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Alien visitors |
| 51 | The Isle of No Return | comic story | 11.67 | script: Jack Kirby, Ed Herron; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins |
| 52 | Challengers of the Unknown #8 | cover reprint (on interior page) | 1 | pencils: Jack Kirby; inks: Wally Wood; letters: Ira Schnapp | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Juhl |
| 53 | The Man Who Stole the Future | comic story | 11.67 | script: Dave Wood, Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins; Marie; Drabny |
| 54 | The Prisoners of Robot Planet | comic story | 12.67 | script: Jack Kirby; pencils: Jack Kirby; inks: Wally Wood; letters: Joe Letterese | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Juhl; Kra |
| 55 | Afterword | foreword, introduction, preface, afterword | 2 | script: John Morrow; pencils: Jack Kirby | Professor Haley |
| 56 | - | illustration | 1 | pencils: Jack Kirby; inks: Jack Kirby | |
| 57 | - | illustration | 1 | pencils: Bruce Timm; inks: Bruce Timm | Jack Kirby |
| 58 | What's Out There? | illustration | 1 | pencils: Jack Kirby; inks: Jack Kirby, Rosalind Kirby, Marvin Stein | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Felix Hesse; ULTIVAC |