Many of the original research and survey monographs ln pure and applied mathematics published by Birkh iuser in recent decades have been groundbreaking and have come to be regarded as found。 ational to the SUbject．Through the MBC Series，a select number ofthese modern classics，entirely uncorrected，are being released in paperback Iand as eBooks)to ensure that these treasures remainaccessible to new generations of students，scholars，and reseat-chers。