Companies involved in many of the largest and most controversial legal clashes of recent decades are seeing a sharp decline in the number of lawsuits filed against them. In recent months, judges have dismissed or challenged tens of thousands of individual cases, in matters ranging from claims of lung damage from asbestos and silica dust to allegations that the diet drug fen-phen caused heart problems. Moreover, fewer new claims like these are being launched, as state and federal courts and legislators attack the methods used by some attorneys to round up plaintiffs for large-scale litigation. There is no comprehensive count ... .