D-99 a science-fiction novel

It's about a special department, Department 99, which is tasked with rescuing humans who have gotten themselves into trouble on other planets. Half the book takes place in the D-99 offices as a city-wide blackout traps them there for hours! Oh noes! Trapped after work! With a generator for power and ample food! They do throw in a complication meant to add some suspense to being stuck at the office after hours. Still, who cares? The other half takes place at various locations where humans need help escaping. Oddly, the book initiates a situation on a planet but never resolves it. But it does resolve several situations already in place at the start. It's almost as if it's part of a serial, although it isn't. The writing is sturdy. The characters are okay if you can ignore the rampant sexism. Still, Tau Zero (which I read soon after) is really only seven years later and has a much more enlightened view of sexual relationships and roles.