I need to know if this book is worth having.

Clymer Publications, Service-Repair Handbook - 240 and 260Z - 1970 to 1974

:classic: you bet I have that one and there is another '70-79 shop manual also by clymer . I found mine on e-bay . :classic:

Below are the ones I have found and would like to know about.

The "How to Restore" by Wick Humble is a great book for restoration work. Some people like the Chilton's books and Clymer's too. Another one that many people like is the Haynes Manuals. The best to have is the Nissan Factory Service Manual for the year of car that you own.