The Documentation Team has published the LibreOffice 4.1 Calc Guide.
Free PDFs of individual chapters and the full book can be downloaded from The Document Foundation’s wiki.
Printed copies can be purchased here. (Published by Friends of OpenDocument Inc.)
This completes a full set of books for LibreOffice 4.0 – 4.1.
See this page or the LibreOffice wiki for a list of books with links to ODT, PDF, and printed copies.