diff --git a/03_Thesis/figures/40_concept/MerlinCollabRecommender.pdf b/03_Thesis/figures/40_concept/MerlinCollabRecommender.pdf
new file mode 100644
index 0000000..c864381
Binary files /dev/null and b/03_Thesis/figures/40_concept/MerlinCollabRecommender.pdf differ
diff --git a/03_Thesis/figures/40_concept/MerlinCollaborativeConfigurator.pdf b/03_Thesis/figures/40_concept/MerlinCollaborativeConfigurator.pdf
new file mode 100644
index 0000000..ee1a3f1
Binary files /dev/null and b/03_Thesis/figures/40_concept/MerlinCollaborativeConfigurator.pdf differ
diff --git a/03_Thesis/figures/40_concept/MerlinConfigurator.pdf b/03_Thesis/figures/40_concept/MerlinConfigurator.pdf
new file mode 100644
index 0000000..65b183a
Binary files /dev/null and b/03_Thesis/figures/40_concept/MerlinConfigurator.pdf differ
diff --git a/03_Thesis/sections/40_concept.tex b/03_Thesis/sections/40_concept.tex
index 31f88fd..1d65650 100644
--- a/03_Thesis/sections/40_concept.tex
+++ b/03_Thesis/sections/40_concept.tex
@@ -1,2 +1,54 @@
 \chapter{Concept}
 \label{ch:Concept}
+
+\section{CAS Configurator Merlin}
+\label{sec:Concept:ConfiguratorMerlin}
+
+\autoref{fig:Concept:ConfiguratorMerlin} shows the architecture of CAS Configurator Merlin.
+\begin{description}
+    \item[M.Core] provides the base of the configurator it checks configuration against all rules in the database, provides possible alternatives on a change that invalidates other parts of a configuration.
+    \item[M.Model] is the editor to create products and rules. These rules can then be uploaded to M.Core.
+    \item[M.Customer] is the customer facing component. It allows a customer to configure a product.
+\end{description}
+
+\begin{figure}
+    \centering
+    \includegraphics{./figures/40_concept/MerlinConfigurator.pdf}
+    \caption{Architecture of Configurator Merlin \cite[Fig. 4.1]{raabKollaborativeProduktkonfigurationEchtzeit2019}}
+    \label{fig:Concept:ConfiguratorMerlin}
+\end{figure}
+
+\section{CAS Group-Configurator}
+\label{sec:Concept:GroupConfigurator}
+
+\citeauthor{raabKollaborativeProduktkonfigurationEchtzeit2019} extends CAS Merlin Configurator in his thesis to allow simultaneous configuration. The extended architecture is shown in \autoref{fig:Concept:CollaborativeConfiguratorMerlin}.
+He only makes changes to M.Customer which is renamed to M.Collab-Customer and introduces a new component M.Collab.
+
+\begin{description}
+    \item[M.Collab] is a node.js server application that communicates with M.Core via REST-API and with M.Collab-Customer via WebSocket. It sits in between M.Collab-Customer and M.Core and handles all processing regarding collaborative configuration.
+    \item[M.Collab-Customer] a modified version of M.Customer that does all communication via WebSocket and does communicate with M.Collab instead of M.Core.
+\end{description}
+
+\begin{figure}
+    \centering
+    \includegraphics{./figures/40_concept/MerlinCollaborativeConfigurator.pdf}
+    \caption{Architecture of Collaborative Configurator Merlin \cite[Fig. 4.3]{raabKollaborativeProduktkonfigurationEchtzeit2019}}
+    \label{fig:Concept:CollaborativeConfiguratorMerlin}
+\end{figure}
+
+
+\section{Extended Configurator}
+\label{sec:Concept:ExtendedConfigurator}
+
+Extending \citeauthor{raabKollaborativeProduktkonfigurationEchtzeit2019} work a module called M.Recommender is added. Its aim is to provide a recommendation server that holds all the data needed for recommendations. M.Collab and M.Collab-Customer have to be modified to allow taking in preferences and to show  recommendations. The recommender engine is set up to be in a separate system which allows the easier replacement and the usage of different technologies. The extended architecture is shown in \autoref{fig:Concept:RecommenderForCollaborativeConfiguratorMerlin}.
+
+\begin{description}
+    \item[M.Recommender] is a new system that will get queried from M.Collab for recommendations, when the configuration changes. M.Recommender will return recommendations which then can be presented to users by M.Collab-Customer.
+\end{description}
+
+\begin{figure}
+    \centering
+    \includegraphics{./figures/40_concept/MerlinCollabRecommender.pdf}
+    \caption{Architecture of Collaborative Configurator Merlin with an added recommender system.}
+    \label{fig:Concept:RecommenderForCollaborativeConfiguratorMerlin}
+\end{figure}
\ No newline at end of file