Experimental physicist Rainer Blatt has carried out trail-blazing experiments in the fields of precision spectroscopy, quantum metrology and quantum information processing. He works with atoms caught in ion traps, which he manipulates using laser beams. This work is based on joint work with, and suggestions made in the mid-1990s by theorists Ignacio Cirac and Peter Zoller. In 2003 Blatt’s group was able to realize for the first time the proposed Cirac-Zoller entangling operation and in 2004, Blatt’s working group succeeded for the first time in transferring the quantum information of one atom in a totally controlled manner onto another atom (teleportation). The science journal Nature reported the experiment and gave it pride of place on the cover. Two years later, Rainer Blatt’s working group already managed to entangle up to eight atoms in a controlled manner. The creation of this first “quantum byte” (qubyte) was a further step on the way towards a quantum computer. 2011 the team managed to push this record to 14 entangled atoms and since 2018 they routinely work with 20 to 50 fully controlled ion qubits. Since 2011 Blatt’s group has taken important steps towards successful quantum error correction and succeeded in encoding a logical qubit with seven physical qubits. The group has also realized a universal quantum simulator, performed open systems quantum simulations and for the first time demonstrated a quantum simulation of a lattice gauge theory. Currently, Blatt’s team routinely operates with several quantum computers, working towards the implementation of scalable quantum computation and quantum simulation, as well as their applications for quantum metrology. In 2022, the group realized for the first time Bell states of two logical quantum bits, which are encoded in a fault-tolerant way and they demonstrated for the first time a universal set of logical gates for quantum computation with trapped ions.