Basic database normalisation is covered in a lot in introductory texts about learning SQL, such as the Sams "Teach yourself X in 24 Hours" series.  These usually go up to third normal form as this is the most an analyst will usually need to know, and whilst they cover the basic logic normalisation it is really only a brief overview.  My introduction to Relational Algebra was from a book called "Access Database Design & Programming: Creating Programmable Database Applications with Access 97, 2000, 2002 & 2003" by Steven Roman.  I purchased it for a section on Visual basic, but found the section on Database design fascinating and was much more advanced than the title of the book, or its focus on Access, would suggest.  This is as good an introduction to database design and normalisation, up to Boyce Codd Normalisation, as Itzik Ben-gan's introduction to Set Theory is to advanced query design.