This is the third thread on this, and in this Forum. I am therefore posting my same message as I posted in the other two threads:
In the interests of full disclosure: This is an organization that charges money. Whether PDFs are useful to you will have to be your decision.
"Our goal is to provide Free public access for a month to 2 Million eBooks. During the rest of the year you may continue to download your selection of about 500,000 PDF eBooks by joining the World Public Library. Annual membership is only $8.95 per year."