Wagner's Salesforce Playbook
With more than 100 pages, 20+ ready to use plays, 15+ free app listings and the learnings of my 6 years working with Salesforce, this book aims to help you get the maximum value from your Salesforce CRM.
Salesforce CRM - The Definitive Admin Handbook - Third Edition
Mastering Application Development with Force.com
Salesforce Reporting and Dashboards
Advanced Apex Programming for Salesforce.com and Force.com