Two good books at a screaming deal with free shipping.

If you are like me and want to learn everything about locks or you are a locksmith, someone that is in need of the best information from two of the best minds of today in locks, here is the best deal I have seen in 10 years. There is a good bit of basic lock history in the front of Master Keying by the Numbers. - Dean Nickel, CJIL, CPL
(posting for BBE, Opinion is mine)
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Prices good until 7/01/13
Master Keying by the Numbers
Fifth Edition, Hard Bound with 399 printed pages covering;

• Terminology
• Cylinder designs and specifications
• The Premise Survey
• Hardware Schedules
• The Standard Key Coding System
• List format progression
• The Standard Progression Format
• The Matrix Format
• Intelligent Cross Keying
• Key Control Programs
• Encryption Techniques
• Construction Keying

$65.00

The Core of the Matter

Second Edition, Hard Bound with 342 printed pages covering every brand and type of Large and Small Format Interchangeable Core produced. This book is the most complete source for interchangeable core information available anywhere. Brands covered are;
ASSA, New and Old style Best Style SFIC Corbin Russwin New and Old Style Dominion Dom ILCO (EHL) Key Bypass Kaba Gemini Lockwood Medeco 32 Series Medeco 31 Series	Reading Sargent 6300 Sargent Signature Sargent Old Style Sargent Keso Sargent Union Locks Schlage LFIC Schlage G Lock Segal Yale 1210, 1220 and Medeco 31 Series $65.00

http://locksoft.com/books/

I agree with Halflock's opinion, excellent information, much of which is not available elsewhere. Note well that the sale prices are only good until 7/1/13. One caveat, the author and publisher make every attempt to restrict sales to bonafide security professionals only. They are not offered for sale to the general public. My 2 cents.

Pete Schifferli