Which kind of transmission line primer depends somewhat on what kind of transmission line applications you are interested in: 1)planar - stripline, slotline, other PCB implementations, 2)those for RF transmission - coaxial, twinlead, etc. 3)Waveguide.
The simplest short primer without heavy theory would be: The ARRL Handbook. This is published every year (I think?). However, my 1991 edition at hand spends only 16 pages directly on transmission lines. The ARRL may have a seperate book on transmission lines.
Another source at hand with directly usuable formulas for many different balanced and unbalanced types is Transmission Line Design Handbook by Brien Waddell, Artech House Pub.
For planar types and PCB applications check out High-Speed Digital Design - A Handbook of Black Magic by Howard Johnson & Martin Grahm, Prentice Hall Pub. This book is great for design issues and pratical solutions.
I am sorry I wasn't clear enough. I am not looking for certain formulas to calculate the transmission line parameters. Rather I am looking for a primer on definition of balanced/unbalanced, baluns etc. I have a pile of book about RF but none of them really goes deeply into this. Maybe someone knows a website with such information.