Springer has made all digital textbooks more than 10 years old available for free on their website. This equates to thousands of important texts that range in disciplines from cognitive learning to pattern recognition through mathematics.
There has been a ton of conjecture on what free actually means, Springer has cleared the air by updating their terms of service. The company states they are for “You may solely for private, educational, personal, scientific, or research purposes access, browse, view, display, search, download and print the Content.”
Have you heard of Springer before? If not, they are basically the worlds second largest academic publisher. They primarily market their collection to researchers and students. They have over one millions textbooks, scientific documents from journals, books, series, protocols and reference works.