The Cat Who Turned On and Off (Cat Who #3) by Lilian Jackson Braun
New mass market paperback (cover may vary).
Brilliant Siamese cats Koko and Yum Yum help reporter Jim Qwilleran solve a complicated murder plot in this mystery in the bestselling Cat Who series.
When Qwilleran decides to do a feature story on Junktown, he gets more than he bargained for. Not the dope den he anticipated, Junktown is a haven for antique dealers and collectors--as strange a lot as the crafty reporter has ever encountered. When a mysterious fall ends the career--and the life--of one of Junktown's leading citizens, Qwilleran is convinced it was no accident. But, as usual, it takes Koko to prove he's right.