I added Pantone+ color book to the path:
C:\Program Files\Adobe\Adobe Photoshop CS4 (64 Bit)\Presets\Color Books
but Photoshop still does not know about Pantone+ color book after reload.
The Pantone+ book still does not present in the Swatches menu list.
So how to add Pantone+ color book to Photoshop?
If you add a Panotone Color book which is a .acb file then it shows when you do a Image>Mode>Duotone conversion or if yo click on Color Libraries in the Color picker.
In order for the colors in a Color Book to show in the swatches panel, one needs a .aco files like illustrated below that contain swatches of the particular Color Book colors. They would go in C:\Program Files\Adobe\Adobe Photoshop CS4 (64 Bit)\Presets\Color Swatches.