If you are a member of a subscribing institution, then by clicking on this Springerlink pointer, your browser should look like the image below. The blue `Download Book' button will allow you to download a free e-book. On the other hand, if the Springer Web server does not recognize your computer's IP address as that of a subscribing institution, then the blue `Download Book' button will be replaced with a paid `Get Access' button. Note the MyCopy option in the lower right corner of the browser, which always appears together with the `Download Book' button.
By selecting the MyCopy option above, you can also obtain the low-cost ($25) paperback edition (grayscale figures), in case you prefer to work with physical books rather than the (free) pdf. The MyCopy versions are created for the convenience of members of subscribing institutions by materializing the e-book in physical form. The MyCopy version can only be obtained from the Springerlink site by members of specific institutions, whereas the official hard-cover (with color figures), can be obtained by anyone from all channels such as Springer, Amazon, or Barnes and Noble. Interestingly, this approach applies to the vast majority of Springer Computer Science books, and the number of subscribing institutions is surprisingly large. As far as I know, the majority of universities in US, Europe, Australia and New Zealand and many corporate research labs are subscribers. This is one of the reasons that make Springer such a great publisher both for authors and readers.
If you are not a member of a subscribing institution, there are other ways of obtaining discounts. If you are an author of any Springer book or a journal article, then you can obtain a 40% discount on Springer hardcover and e-books by using the approach described here. I am not completely certain whether the MyCopy price can be combined with the author discount because the Springer Web site says that there are some restrictions on combining discounts. However, I have always been able to successfully combine the two and buy Springer MyCopy books (including some amazing $170+ handbooks) for 40% of the $25 MyCopy price, which is around $15.