Paul Carson's protagonist Frank Ryan has a problem. Several, in fact. As told in Carson's new novel "Betrayal," Ryan is abducted while performing his duties as a medical officer in a Dublin prison. One problem is that no one believes Ryan's version of events, in part because his girlfriend seems to have vanished and Ryan may have had something to do with it. So, in search of answers, Ryan becomes enmeshed in a global mystery. Carson (who is a practicing physician) has drawn comparisons to Michael Palmer and Tess Gerritsen, so if you like those writers, give Carson a try. ($25.95 / 400 pages / St. Martin's Press)