First published in 1956, by Paul French (a Pen Name for Isaac Asimov). This is a Science Fiction action-adventure with Mystery Fiction elements targeted towards a juvenile audience. The fourth book of the series, Lucky Starr and Bigman find the saboteurs of Mercury.
Lucky and Bigman meet Scott Mindes not long after arriving, who persuades them to follow him out on an excursion to the dark side of Mercury. Mr Mindes is in charge of Project Light, an experiment attempting to prove that sunlight can be manipulated through hyperspace. He leads them outside on the prefix of showing the sights of Mercury, such as the "white ghost" (light from the corona of the sun) and the "red ghost" (light from jets of hydrogen gas or solar flares) of this planet. He actually took them outside to discuss the sabotage that his project has undergone since its inception. And to kill Lucky.
After knocking him unconscious and going back to the dome, they meet Dr Gardoma, the one medical doctor they have for the observatory. He's Mr Mindes's best friend in the dome and tries to convince Lucky that Mindes had merely gone temporarily crazy as a result of the strain he had been under. Jonathan Urteil enters the medical area and confirms for them that Mindes had been under significant pressure, but offers a different explanation for the murder attempt.
Mr Urteil works for Senator Swenson, and the two men dislike the Council of Science for promoting the wasteful expenditure of government taxes on scientific research and wished to gain power by taking it from the Council. Urteil suggests that Mindes had attempted to kill Lucky in a calculated attempt to prevent the Council from learning what a failure Project Light really was. He's established quickly as a Jerkass with no friends on Mercury, but Senator Swenson is a powerful ally on Earth.
Finally, Lucky and Bigman meet Dr Peverale, the director of the Mercury Observatory, and Dr Cook, his second-in-command. Dr Cook is a quiet man, not given to much conversation, but clearly hates Urteil as much as the rest do. Dr Peverale, however, ignores Urteil as much as possible and instead tries to convince Lucky that the people sabotaging Project Light must be the Sirians. Agreeing to the possibility, Lucky and Bigman plan an expedition to the abandoned mines, to search out any hidden Sirians or native Mercurians. Unexpectedly, they find evidence for both!
Lucky Starr and the Big Sun of Mercury provides examples of:
- Billed Above the Title:
- The original 1956 cover credits Paul French above the title and plays with the sizing (and italics) of both his name and the title itself.
- The 1978 Fawcett Crest cover credits Isaac Asimov, writing as Paul French before listing the title. In this case, Dr Asimov's name is larger than the subtitle of and the Big Sun of Mercury, but Lucky Starr is written much larger.
- Dedication: This volume is dedicated to Dr Asimov's daughter, whom he calls "Robyn Joan". She was a newborn while he was writing this story.
- Delicious Distraction: Bigman and Urteil are under attack by a Mercurian life-form with tentacles. After wrenching away his blaster, Bigman makes some modifications to it and throws it away. Enticed by the overloading blaster, the creature leaves the two humans alone, and Bigman drags Urteil out of the tunnels and back to the dome to report on the attack.
- Excited Show Title!: A few chapters end in exclamation marks: Chapter 11: Saboteur!
- Fictional Field of Science: Hyperoptics is a brand-new field of science that studies the effects of photons in hyperspace. Mr Mindes is trying an experiment which will result in being able to control how sunlight hits the Earth.
- His Name Is...: While a Sirian robot is breaking down, Lucky asks who gave it orders, and it barely manages one sound, "Er- Er-". Bigman immediately deduces that the robot meant Urteil, but Lucky disagrees, telling him that it was more likely to mean "Earthman", which would be Dr Peverale, who had once visited the Sirian system and stole the robot assigned to him.
- Industrialized Mercury: Lucky visits a scientific outpost on Mercury, which has mining operations to make the outpost more self-sufficient. The primary project occurring is Project Light, where hyperspace is used to manipulate sunlight, but the project itself is facing setbacks.
- Legendary in the Sequel: Much to Lucky's consternation, he's been getting plenty of publicity amoung certain circles. It's bad because being famous will make it more difficult to go undercover as Williams if people already know who he is. Oddly, Dr Peverale doesn't seem to recognize Lucky, despite moving in the same circles.
- Look Behind You: Bigman Jones is holding Jonathan Urteil at blaster-point in the Mercury mines when Urteil looks over Bigman's shoulder and says that Lucky Starr is coming back. Bigman looks, and Urteil quickly gains the upper hand.Never in his life had Bigman so hated himself. To be tricked and hoodwinked this way. He almost deserved death. He would almost rather die than ever have to face Lucky and say, "He looked behind me and said you were coming so I turned..."
- No Gravity for You: Inverted when Urteil and Bigman were fighting in Mercury-normal gravity. During their fight, Bigman tossed him up in the air, and someone tried to murder Urteil by turning on the Earth-like pseudogravity at the peak of the arc.
- Robot Names: The robot who had been sabotaging Project Light was created in the Sirius system and given the serial number RL-726.
- Tagline: "On a planet like Mercury, suntanning could be lethal!" — 1984 Del Rey cover
- Subspace or Hyperspace: Hyperspace travel made settling other star systems possible, although, as is common for Asimov's works, it's not used for interplanetary travel.
- Tidally Locked Planet: In this story, Mercury is tidally locked with the sun, creating a day-side and night-side.
- Video Phone: Lucky and Bigman are assigned a room with a "Talkie", two-way communication device which includes video and a "receiving plate" (rather than calling it a video camera).