diff --git a/docs/src/SUMMARY.md b/docs/src/SUMMARY.md
index bcd4ffea37..9cc0cbf517 100644
--- a/docs/src/SUMMARY.md
+++ b/docs/src/SUMMARY.md
@@ -12,5 +12,8 @@
 - [Baby Fuzzer](./baby_fuzzer.md)
 
 - [Core Concepts](./core_concepts/core_concepts.md)
-  - [Executor](./core_concepts/executor.md)
   - [Observer](./core_concepts/observer.md)
+  - [Executor](./core_concepts/executor.md)
+  - [Feedback](./core_concepts/feedback.md)
+  - [Input](./core_concepts/input.md)
+  - [Corpus](./core_concepts/corpus.md)
diff --git a/docs/src/core_concepts/core_concepts.md b/docs/src/core_concepts/core_concepts.md
index 46b3960f44..2da1afbb02 100644
--- a/docs/src/core_concepts/core_concepts.md
+++ b/docs/src/core_concepts/core_concepts.md
@@ -1,3 +1,7 @@
 # Core Concepts
 
+LibAFL is designed around some core concepts that we think can effectively abstract most of the other fuzzers designs.
+
+In this chapter, we discuss these concepts, provide some examples related to other fuzzers and some details how the defined entities maps to the code in Rust.
+
 
diff --git a/docs/src/core_concepts/corpus.md b/docs/src/core_concepts/corpus.md
new file mode 100644
index 0000000000..361eb33c64
--- /dev/null
+++ b/docs/src/core_concepts/corpus.md
@@ -0,0 +1 @@
+# Corpus
diff --git a/docs/src/core_concepts/executor.md b/docs/src/core_concepts/executor.md
index 3fddc32644..965280e07e 100644
--- a/docs/src/core_concepts/executor.md
+++ b/docs/src/core_concepts/executor.md
@@ -1 +1,10 @@
 # Executor
+
+In different fuzzers, the concept of executing the program under test each run is now always the same.
+For instance, for in-memory fuzzers like libFuzzer an execution is a call to an harness function, for hypervisor-based fuzzers like [kAFL](https://github.com/IntelLabs/kAFL) instead an entire operating system is started from a snapshot each run.
+
+In our model, an Executor is the entity that defines not only how to execute the target, but all the volatile operations that are related to just a single run of the target.
+
+So the Executor is for instance reponsible to inform the program about the input that the fuzzer wants to use in the run, writing to a memory location for instance or passing it as a parameter to the harness function.
+
+It also holds a set of Observers, as thay are related to just a single run of the target.
diff --git a/docs/src/core_concepts/feedback.md b/docs/src/core_concepts/feedback.md
new file mode 100644
index 0000000000..c4a1060c53
--- /dev/null
+++ b/docs/src/core_concepts/feedback.md
@@ -0,0 +1,3 @@
+# Feedback
+
+
diff --git a/docs/src/core_concepts/input.md b/docs/src/core_concepts/input.md
new file mode 100644
index 0000000000..135b6af33f
--- /dev/null
+++ b/docs/src/core_concepts/input.md
@@ -0,0 +1 @@
+# Input
diff --git a/docs/src/core_concepts/observer.md b/docs/src/core_concepts/observer.md
index 94e0f8b987..65ba1ec920 100644
--- a/docs/src/core_concepts/observer.md
+++ b/docs/src/core_concepts/observer.md
@@ -1 +1,5 @@
 # Observer
+
+An Observer, or Observation Channel, is an entity that provide an information related to a single run of the program under test to the fuzzer.
+
+
diff --git a/docs/src/getting_started/crates.md b/docs/src/getting_started/crates.md
index 1745da0494..841094e076 100644
--- a/docs/src/getting_started/crates.md
+++ b/docs/src/getting_started/crates.md
@@ -5,9 +5,36 @@ Each one has its self-contained purpose, and the user may not need to use all of
 
 Following the naming convention of the folders in the project's root, they are:
 
-- libafl, the main crate that contains all the components needed to build a fuzzer
-- libafl_derive, a proc-macro crate paired with the libafl crate
-- libafl_targets, a crate that expose, under feature flags, pieces of code to interact with targets
-- libafl_cc, a library that provide some utils to wrap compilers and create source level fuzzers.
+### libafl
 
+This is the main crate that contains all the components needed to build a fuzzer.
 
+This crate has the following feature flags:
+
+- std, that enables the parts of the code that use the Rust standard library. Without this flags, libafl is no_std.
+- derive, that enables the usage of the `derive(...)` macros defined in libafl_derive from libafl.
+
+By default, std and derive are both set.
+
+### libafl_derive
+
+This a proc-macro crate paired with the libafl crate.
+
+At the moment, it just expose the `derive(SerdeAny)` macro that can be used to define metadata structs.
+
+### libafl_targets
+
+This crate that exposes, under feature flags, pieces of code to interact with targets
+
+Currently, the supported flags are:
+
+- pcguard_edges, that defines the SanitizerCoverage trace-pc-guard hooks to track the executed edges in a map.
+- pcguard_hitcounts, that defines the SanitizerCoverage trace-pc-guard hooks to track the executed edges with the hitcounts (like AFL) in a map.
+- libfuzzer, that expose a compatibility layer with libFuzzer style harnesses.
+- value_profile, that defines the SanitizerCoverage trace-cmp hooks to track the matching bits of each comparison in a map. 
+
+### libafl_cc
+
+This is a library that provides some utils to wrap compilers and create source level fuzzers.
+
+At the moment, only the Clang compiler is supported.
diff --git a/libafl/Cargo.toml b/libafl/Cargo.toml
index 2c1506c38e..72aafb481c 100644
--- a/libafl/Cargo.toml
+++ b/libafl/Cargo.toml
@@ -32,7 +32,6 @@ harness = false
 [features]
 default = ["std", "anymapdbg", "derive"]
 std = [] # print, sharedmap, ... support
-runtime = [] # a runtime for clang inmem-executor
 anymapdbg = ["serde_json"] # uses serde_json to Debug the anymap trait. Disable for smaller footprint.
 derive = ["libafl_derive"] # provide derive(SerdeAny) macro.
 llmp_small_maps = [] # reduces initial map size for llmp