Seconding the recommendation for Practical Electronics for Inventors as a comprehensive and self-contained book for learning electronics at a hobbyist level.
Art of Electronics is also a good book but needs to be read with a discerning eye to place everything in the appropriate context: some sections are important, some are premature optimization for hobby-level projects, and some are flat out obsolete. I feel it's better used as a reference book than read cover to cover.
