How to develop innovative architectures based on emerging molecular devices? The simple yet ambitious objective of "Molecular Electronics Materials, Devices and Applications" is to give the reader the necessary information to understand the challenges and opportunities of this recent field of research. In order to provide a good overview and understanding, the main molecular devices are first presented. A complete set of presentation and discussion of the actual molecular architectures follows. Nevertheless, another goal of "Molecular Electronics Materials, Devices and Applications" is also to promote a practical approach. As a starting point for future developments, a pragmatic methodology for VHDL-AMS device modelling and circuit design based on experimental data is then proposed. It includes an original fault tolerant memory architecture based on molecular electronics.