I must have borrowed his one from my grade school's library three or four times. It's a choose your own adventure. The main things I remember about it are that it takes place on the Moebius Express, an interplantary ship that's in the shape of a Moebius strip, and that the alien murder victim has a legless body that's shaped like a triangle pointing downward.
The Interplanetary Spy series picked me up once I started getting a bit bored with Choose Your Own Adventure's randomness. Maybe I was tired of the randomness or absurdity, although Internet reviews did show that CYoA had a few clunkers. But it was hard not to love IS. Wild pictures of crazy alien life forms! Each fork was a choice that resulted in death if you did something wrong! Or, if not death, an embarrassing rebuke. The writing was sharp and snappy, and it ended too soon after number 12. Those books gave me the coolest nightmares.
The best of them is The Star Crystal. It starts as a reconnaisance mission where you need to help guard the priceless Star Crystal. But then someone breaks in and steals it and murders a fellow Interplanetary Spy! You're sent across the breadth of the Mobius Express, a starship shaped like a mobius strip. It's all pretty linear, and you have to interrogate artists who are suspects, including Freeba and his weird fast food drive-up microphone mouth, or Cicelia and her conch shaped instrument. It's great fun and the the deaths are also worth exploring, especially when Callisto touches you with his warp chisel! The puzzles aren't especially hard, but they keep the pace going.
CYoA never saw anything like Interplanetary Spy for straight choices, and I only wish it had lasted longer. But it was maybe too much of a niche. Still I remember the thrill of buying a copy on that new eBay site, to replace the ones given away, and finding it was as good as I remembered.