for obtaining a sure piano technique - Zur Erlangung einer sicheren Klaviertechnik-Ernst Von Dohnanyi's Essential Finger Exercises is an excellent book which helps pianists to develop and secure technique. These forty exercises will help to strengthen your fingers and help to give you greater technical control in performance.
Ernst von Dohnanyi: Essential Finger Exercises: Piano: Instrumental Tutor
Essential Finger Exercises For Obtaining A Sure Piano Technique