The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From MavEtJu software:
The original L-Space application was for tracking the status of the books in my Discworld collection: Which do I own, how many have I already read, which ones are still missing, and also for the Dutch language please Over time it got more and more features: Instead of only a list of books for a single series, you can tag which ones you own and which ones you have read, plus background information like the characters and themes of each of the books. Also the titles of non-English languages like Dutch, German, French, Spanish and Portuguese were added. This app contains the list of books of the Wheel of Time series, written by Robert Jordan.