EXHIBIT
10.18

    


    JOINDER
TO REGISTRATION RIGHTS AGREEMENT

     

    This
JOINDER AGREEMENT (this “Joinder Agreement”), dated as of November ___, 2009, to
the Registration Rights Agreement (the
“Agreement”)  dated  as of November 29, 2007, by and among
Camden Learning Corporation, a Delaware corporation (the “Company”), and the
Investors is made by and between the Company and the stockholder listed on the
signature page hereof (the “Stockholder”).  All capitalized terms used
in this Joinder Agreement without definition shall have the meanings ascribed
thereto in the Agreement.

    


    WHEREAS,
in connection with the Company’s initial public offering consummated on December
5, 2007, the Company issued 1,562,650 shares of restricted common stock, par
value $0.0001 per share (the “Restricted Stock”) to the Investors with such
Restricted Stock subject to the terms and conditions of that certain Securities
Escrow Agreement dated November 29, 2007, as amended; and

    


    WHEREAS,
the Company has now entered into that certain Agreement and Plan of
Reorganization as amended and restated in its entirety on August 11, 2009 and
further amended on October 26, 2009 by Amendment No. 1 to the Amended and
Restated Agreement and Plan of Reorganization, pursuant to which Dlorah
Subsidiary, Inc., a newly formed, wholly-owned subsidiary of Camden (‘‘Merger
Sub’’), will merge with and into Dlorah, Inc., a South Dakota corporation
(Dlorah, Inc., together with its divisions and subsidiaries, is referred to
herein as “Dlorah”), with Dlorah surviving as a wholly-owned subsidiary of
Camden, as a result of which the stockholders of Dlorah will contribute all of
the outstanding capital stock of Dlorah to Camden in exchange for shares of a
newly created class of Camden common stock, common stock purchase warrants and
restricted shares of Camden’s currently authorized common stock (the
“Acquisition”); and

     

    WHEREAS,
in connection with the Acquisition and pursuant to the Share Transfer Agreement
dated November __, 2009 by and between Camden Learning, LLC (“CL LLC”) and the
Stockholder, CL LLC has agreed to transfer [NUMBER] of shares of Restricted
Stock to the Stockholder (the “Transferred Stock”); and

    


    WHEREAS,
the Agreement sets forth the terms upon which the Restricted Stock can be
registered, and as transferee of a certain portion of the Restricted Stock, the
Stockholder wishes to be joined to the Agreement with respect to the Transferred
Stock.


    
      
         


      

      
         


        
          

        

      

      
         


      

    


    NOW,
THEREFORE, the parties hereto agree as follows:

    


    1.           Joinder.

    


    The
Stockholder hereby agrees to become a party to the Agreement and to be bound by
all of the provisions thereof as if a signatory thereto, and shall have all of
the rights and privileges of an original signatory to the Agreement with respect
to the Transferred Stock.

    


    
      2.         
Notices.

    

    


    The provisions of Section 6.3 of the
Agreement shall be amended to add the following notice information for the
Stockholder:

    


    If to the
Stockholder to:

    


    [INSERT]

    


    A copy of
any notice sent to the Stockholder hereunder shall be sent to:

    


    [INSERT]

    


    3.            Miscellaneous.

    


    (a)           Governing
Law.  This Joinder Agreement shall be governed by, interpreted
under, and construed in accordance with the internal laws of the State of New
York applicable to agreements made and to be performed within the State of New
York, without giving effect to any choice-of-law provisions thereof that would
compel the application of the substantive laws of any other
jurisdiction.  Each of the parties hereby agrees that any action,
proceeding or claim against it arising out of or relating in any way to this
Joinder Agreement shall be brought and enforced in the courts of the State of
New York or the United States District Court for the Southern District of New
York (each, a “New York Court”), and irrevocably submits to such jurisdiction,
which jurisdiction shall be exclusive. Each of the parties hereby waives any
objection to such exclusive jurisdiction and that such courts represent an
inconvenient forum.

    


    (b)           Entire
Agreement.  This Joinder Agreement contains the entire
agreement of the parties hereto with respect to the subject matter hereof and,
except as expressly provided herein, may not be changed or modified except by an
instrument in writing signed by the party to be charged.  This Joinder
Agreement may be executed in one or more counterparts and delivered by
facsimile, each of which shall constitute an original, and together shall
constitute one and the same instrument.

    


    (c)           Headings.  The
headings contained in this Joinder Agreement are for reference purposes only and
shall not affect in any way the meaning or interpretation thereof.

    


    (d)           Binding
Effect.  This Joinder Agreement shall be binding upon and inure
to the benefit of the respective parties hereto and their legal representatives,
successors and assigns.


    
      
         


      

      
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    (e)           Counterparts. This
Agreement may be executed in several counterparts each one of which shall
constitute an original and may be delivered by facsimile transmission and
together shall constitute one instrument.


    
      
         


      

      
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    WITNESS
the execution of this Joinder Agreement as of the date first above
written.

    


    
      
        	
                [Insert
      New Stockholder]

              
	 
      	 
      
	
                By:

              	 
      
	
                Name:

              	 
      
	
                Title:

              	 
      


      

    

    


    
      
        
          	
                  CAMDEN
      LEARNING CORPORATION

                
	 
      	 
      
	
                  By:

                	 
      
	 
      	
                  Name:
      David Warnock

                
	 
      	
                  Title:
      Chairman, President and Chief Executive
Officer

                


        

      

    


    
      
         


      

      
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