When  an individual purchases an apartment in a cooperative corporation, it is actually the cooperative
corporation which owns the real estate (ie. the  building and usually, but not always, the land
underneath).   The purchaser is buying personal property in the form of a stock certificate and
proprietary lease.   The stock certificate evidences the individual's ownership interest in the
corporation, and the proprietary lease contains the rules by which the shareholder must abide.   The
purchaser must, in most cases, obtain approval from the corporation's board of directors before she is
able to proceed to closing.    

In a condominium, the purchaser is buying real estate and is given a deed to show her ownership
interest.  The purchaser of a condominium owns the common elements of the condominium (ie. the
elevators, hallways, lobby, etc) in common with all other unit owners.   When buying a condominium
unit the Seller, in most cases, must obtain the condominium's waiver of its right of first refusal.  In
essence, this means that either the condominium must match the purchaser's offer to buy, or waive its
right of first refusal allowing the transaction to proceed.  It is for this reason, that it is generally much
easier to purchase a condominium than a coop.
RUBIN & GOLD LLP        
NYC REAL ESTATE LAWYERS
UNDERSTANDING  COOPS & CONDOS