Preface; Acknowledgments; 1. Introduction; Part I. The Status Quo: 2. Quantum theory from Hilbert-spaces; Part II. The Informational Approach: 3. The framework; 4. The new principles; 5. Causal theories; 6. Theories with local discriminability; 7. The purification principle; Part III. Quantum Information without Hilbert Spaces: 8. Encoding information; 9. Three no-go theorems; 10. Perfectly discriminable states; 11. Identifying pure states; 12. Diagonalization; Part IV. Quantum Theory from the Principles: 13. Conclusive teleportation; 14. The qubit; 15. Projections; 16. The superposition principle; 17. Derivation of quantum theory; References; Index. sakriti opis