hardware needs for ccna prep

I'm trying to find out info on what I will need in the way of hardware for preparing for one, and preferably more of Cisco's certifications starting with the CCNA. Is more than one router needed or recommened for simulation and training purposes? What should be the least amount I could

ccna exam(s)

Could someone please tell me how many tests there are in the CCNA track? I have been reading Cisco Press' Introduction to Cisco Router Configuration, but, oddly, nowhere in this book can I find anything but the most general informatin on obtaining this certification. Thanks in advance.