A good suggestion for data access is
ADO 2.0 Programmer's Reference - (January 21, 1999)
Author: David Sussman and Alex Homer
Publisher: WROX
ISBN: 1-861001-83-5
This book introduces ADO 2.0 and provides a complete guide to using ADO for the rapid development of your data applications.

Check out Ken Levy web site in the book section you will find good suggestion.
http://www.classx.com/

For class and OOP concept check Steven Black web site in the Book section
http://www.stevenblack.com/

BTW Steven Black will be presenting in Montreal Next week. Do not mist this presentation. For more information check our web site:
http://www.transformation.com/mfug/

>I want to buy a book or two on VB, but I want your suggestions first.
>
>I have been developping with VFP for over 9 years and have worked with VB 5 for 6 months 2 years ago, so I'm not a complete beginner.
>
>What I'm looking for is a reference book where I can refer when I want to know how things are done with VB (connecting to database, creating classes, etc.) and that can teach me how to create a 3-tiers application using COM.
>
>My guess is that I will need two differents books, one as a general reference and one for 3-tiers development, but I'm looking for your suggestions.
>
>TIA