I would like to know if the head first 3rd edition contains all of the information needed to pass the PMP exam. The reason I ask is that I can not see some topics and formula in the 3rd edition that appear in other books like six sigma, some of the PERT, depreciation and estimate formulas to name a few. Is there anyone that has used the 3rd edition as their main study source and passed the PMP exam? I can only afford one study source is the Head First 3rd suitable? Your feedback is much appreciated it would be even better if someone from O'Reilly would comment as I wish to purchase their product if suitable. Thank you in advance.