Fans of Dr. Alex Delaware and his friend and partner, LAPD Detective Milo Sturgis, have a hair-raising five hours in store for them, as John Rubinstein, always one of my favorites, narrates Jonathan Kellerman's latest psychological thriller, Monster (abridged, $25, 0375407995). Delaware has dealt with many elusive, arrogant killers, but this string of gruesome murders has him baffled, and Milo miffed. The only thing that ties these cases together is the almost incoherent babbling of a nonfunctional psychotic who has been locked up in a high security hospital for the criminally insane for 16 years. As the grisly killings mount, Sturgis and Delaware try desperately to put the disparate shreds together and when they do, they find a monster who gives new meaning to the word. Sukey Howard reports on spoken word audio each month.