diff --git a/Project.toml b/Project.toml
index 1f01229..7bfc860 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,10 +1,14 @@
 name = "GeometricBase"
 uuid = "9a0b12b7-583b-4f04-aa1f-d8551b6addc9"
-authors = ["Michael Kraus"]
 version = "0.12.7"
+authors = ["Michael Kraus"]
+
+[deps]
+Unicode = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
 
 [compat]
-julia = "1.6"
+Unicode = "1.10"
+julia = "1.10"
 
 [extras]
 SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
diff --git a/src/GeometricBase.jl b/src/GeometricBase.jl
index c981cd4..1240943 100644
--- a/src/GeometricBase.jl
+++ b/src/GeometricBase.jl
@@ -1,21 +1,22 @@
 module GeometricBase
 
-    include("Config.jl")
-    include("Utils.jl")
+include("Config.jl")
+include("Utils.jl")
 
-    include("methods.jl")
-    include("types.jl")
+include("methods.jl")
+include("types.jl")
 
-    include("abstract_problem.jl")
-    include("abstract_method.jl")
-    include("abstract_integrator.jl")
-    include("abstract_solution.jl")
-    include("abstract_solver.jl")
-    include("abstract_solver_state.jl")
+include("abstract_problem.jl")
+include("abstract_method.jl")
+include("abstract_integrator.jl")
+include("abstract_solution.jl")
+include("abstract_solver.jl")
+include("abstract_solver_state.jl")
 
-    include("data/system_types.jl")
-    include("data/data_types.jl")
-    include("data/geometric_data.jl")
-    include("data/state_variables.jl")
+include("data/system_types.jl")
+include("data/data_types.jl")
+include("data/geometric_data.jl")
+include("data/state_variables.jl")
+include("data/state.jl")
 
 end
diff --git a/src/data/state.jl b/src/data/state.jl
new file mode 100644
index 0000000..3f3ec91
--- /dev/null
+++ b/src/data/state.jl
@@ -0,0 +1,139 @@
+using Unicode: normalize
+
+export State
+export solution, state, vectorfield
+
+
+# The `_state` function returns an appropriate empty state for a given state variable.
+# _state(x::Number) = ScalarVariable(x)
+_state(x::TimeVariable) = zero(x)
+_state(x::StateVariable) = StateWithError(zero(x))
+_state(x::VectorfieldVariable) = zero(x)
+_state(x::AlgebraicVariable) = zero(x)
+_state(x::StateWithError) = zero(x)
+
+# The `_vectorfield` function returns an appropriate empty vectorfield for a given state variable.
+# _vectorfield(x::Number) = missing
+_vectorfield(x::TimeVariable) = missing
+_vectorfield(x::StateVariable) = VectorfieldVariable(x)
+_vectorfield(x::VectorfieldVariable) = missing
+_vectorfield(x::AlgebraicVariable) = missing
+_vectorfield(x::StateWithError) = _vectorfield(x.state)
+
+# The `_convert` function returns an appropriate type for any given `AbstractVariable`.
+# In particular, it returns the scalar value of a `TimeVariable`.
+_convert(x::Missing)::Missing = x
+_convert(x::TimeVariable) = value(x)
+_convert(x::AbstractVariable) = x
+
+# Adds a dot or bar to a symbol, indicating a time derivative or vector field, or a previous solution.
+_add_symbol(s::Symbol, c::Char) = Symbol(normalize("$(s)$(c)"))
+_add_bar(s::Symbol) = _add_symbol(s, Char(0x0304))
+_add_dot(s::Symbol) = _add_symbol(s, Char(0x0307))
+
+# Removes a dot or bar from a symbol.
+_strip_symbol(s::Symbol, c::Char) = Symbol(strip(normalize(String(s); decompose=true), c))
+_strip_bar(s::Symbol) = _strip_symbol(s, Char(0x0304))
+_strip_dot(s::Symbol) = _strip_symbol(s, Char(0x0307))
+
+# q̄ = Symbol(join([Char('q'), Char(0x0304)]))
+# q̇ = Symbol(join([Char('q'), Char(0x0307)]))
+# q = Symbol(strip(String(:q̄), Char(0x0304)))
+# q = Symbol(strip(String(:q̇), Char(0x0307)))
+
+
+"""
+Holds the solution of a geometric equation at a single time step.
+
+It stores all the information that is required to uniquely determine the state of a systen,
+in particular all state variables and their corresponding vector fields.
+"""
+struct State{
+    stateType<:NamedTuple,
+    solutionType<:NamedTuple,
+    vectorfieldType<:NamedTuple
+}
+
+    state::stateType
+    solution::solutionType
+    vectorfield::vectorfieldType
+
+    function State(ics::NamedTuple)
+        # create solution tupke for all variables in ics
+        solution = NamedTuple{keys(ics)}(_state(x) for x in ics)
+
+        # create vectorfield vector for all state variables in ics
+        vectorfield = NamedTuple{keys(ics)}(_vectorfield(x) for x in ics)
+
+        # remove all fields that are missing, i.e., that correspond to a variable without vectorfield
+        vectorfield_filtered = NamedTuple{filter(k -> !all(ismissing.(vectorfield[k])), keys(vectorfield))}(vectorfield)
+
+        # create vector field symbols with dotted solution symbols
+        vectorfield_keys = Tuple(_add_dot(k) for k in keys(vectorfield_filtered))
+        vectorfield_dots = NamedTuple{vectorfield_keys}(values(vectorfield_filtered))
+
+        # create state by merging solution fields with filtered vector fields
+        state_fields = merge(solution, vectorfield_dots)
+
+        # create state
+        state = new{typeof(state_fields),typeof(solution),typeof(vectorfield_filtered)}(state_fields, solution, vectorfield_filtered)
+
+        # copy initial conditions to state
+        copy!(state, ics)
+
+        return state
+    end
+end
+
+@inline function Base.hasproperty(::State{ST}, s::Symbol) where {ST}
+    hasfield(ST, s) || hasfield(State, s)
+end
+
+@inline function Base.getproperty(st::State{ST}, s::Symbol) where {ST}
+    if hasfield(ST, s)
+        return _convert(getfield(st, :state)[s])
+    else
+        return getfield(st, s)
+    end
+end
+
+@inline function Base.setproperty!(st::State{ST}, s::Symbol, x) where {ST}
+    if hasfield(ST, s)
+        return copy!(getfield(st, :state)[s], x)
+    else
+        return setfield!(st, s, x)
+    end
+end
+
+
+state(st::State) = st.state
+solution(st::State) = st.solution
+vectorfield(st::State) = st.vectorfield
+
+"""
+    keys(st::State)
+
+Return the keys of all the state variables in the `State`.
+"""
+Base.keys(st::State) = keys(state(st))
+
+"""
+    copy!(st::State, sol::NamedTuple)
+
+Copy the values from a `NamedTuple` `sol` to the `State` `st`.
+
+The keys of `sol` must be a subset of the keys of the state.
+
+# Arguments
+- `st`: the state to copy into
+- `sol`: the named tuple containing the solution values to copy
+"""
+function Base.copy!(st::State, sol::NamedTuple)
+    @assert keys(sol) ⊆ keys(st)
+
+    for k in keys(sol)
+        copy!(solution(st)[k], sol[k])
+    end
+
+    return st
+end
diff --git a/src/data/state_variables.jl b/src/data/state_variables.jl
index 880159a..1a87eed 100644
--- a/src/data/state_variables.jl
+++ b/src/data/state_variables.jl
@@ -5,7 +5,7 @@ export TimeVariable, StateVariable, VectorfieldVariable, AlgebraicVariable
 export Increment, StateWithError, StateVariableWithError, StateVector
 
 export isperiodic, parenttype, verifyrange
-export add!, reset!, periodic, value, vectorfield, zerovector
+export add!, reset!, periodic, value, zerovector
 
 
 """
@@ -29,6 +29,7 @@ Base.:(==)(x::AV, y::AV) where {AV<:AbstractVariable} = parent(x) == parent(y)
 """
 abstract type AbstractScalarVariable{DT} <: AbstractVariable{DT,0} end
 
+Base.:(==)(x::AbstractScalarVariable, y::AbstractScalarVariable) = value(x) == value(y)
 Base.:(==)(x::AbstractScalarVariable, y::Number) = value(x) == y
 Base.:(==)(x::Number, y::AbstractScalarVariable) = y == x
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 768040f..4d57429 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,12 +1,35 @@
 using SafeTestsets
 
-@safetestset "Abstract Problem                                                                " begin include("abstract_problem_tests.jl") end
-@safetestset "Abstract Solution                                                               " begin include("abstract_solution_tests.jl") end
-@safetestset "Abstract Integrator                                                             " begin include("abstract_integrator_tests.jl") end
-@safetestset "Abstract Method                                                                 " begin include("abstract_method_tests.jl") end
-@safetestset "Abstract Solver                                                                 " begin include("abstract_solver_tests.jl") end
-@safetestset "Geometric Data                                                                  " begin include("geometric_data_tests.jl") end
-@safetestset "State Variables                                                                 " begin include("state_variables_tests.jl") end
-@safetestset "Methods                                                                         " begin include("methods_tests.jl") end
-@safetestset "Types                                                                           " begin include("types_tests.jl") end
-@safetestset "Utils                                                                           " begin include("utils_tests.jl") end
+@safetestset "Abstract Problem                                                                " begin
+    include("abstract_problem_tests.jl")
+end
+@safetestset "Abstract Solution                                                               " begin
+    include("abstract_solution_tests.jl")
+end
+@safetestset "Abstract Integrator                                                             " begin
+    include("abstract_integrator_tests.jl")
+end
+@safetestset "Abstract Method                                                                 " begin
+    include("abstract_method_tests.jl")
+end
+@safetestset "Abstract Solver                                                                 " begin
+    include("abstract_solver_tests.jl")
+end
+@safetestset "Geometric Data                                                                  " begin
+    include("geometric_data_tests.jl")
+end
+@safetestset "State Variables                                                                 " begin
+    include("state_variables_tests.jl")
+end
+@safetestset "States                                                                          " begin
+    include("state_tests.jl")
+end
+@safetestset "Methods                                                                         " begin
+    include("methods_tests.jl")
+end
+@safetestset "Types                                                                           " begin
+    include("types_tests.jl")
+end
+@safetestset "Utils                                                                           " begin
+    include("utils_tests.jl")
+end
diff --git a/test/state_tests.jl b/test/state_tests.jl
new file mode 100644
index 0000000..89af6a2
--- /dev/null
+++ b/test/state_tests.jl
@@ -0,0 +1,92 @@
+using GeometricBase
+using Test
+
+using GeometricBase: StateWithError, TimeVariable, VectorfieldVariable
+using GeometricBase: periodic, value
+using GeometricBase: _strip_symbol, _strip_bar, _strip_dot, _add_symbol, _add_bar, _add_dot, _state, _vectorfield
+
+
+@testset "$(rpad("State Helper Functions",80))" begin
+
+    x = rand(3)
+
+    @test _strip_symbol(:q̄, Char(0x0304)) == :q
+    @test _strip_symbol(:q̇, Char(0x0307)) == :q
+
+    @test _strip_bar(:q̄) == :q
+    @test _strip_dot(:q̇) == :q
+
+    @test _add_symbol(:q, Char(0x0304)) == :q̄
+    @test _add_symbol(:q, Char(0x0307)) == :q̇
+
+    @test _add_bar(:q) == :q̄
+    @test _add_dot(:q) == :q̇
+
+    @test _state(TimeVariable(1.0)) == TimeVariable(0.0)
+    @test _state(StateVariable(x)) == StateWithError(StateVariable(zero(x)))
+
+    # @test ismissing(_vectorfield(1))
+    @test ismissing(_vectorfield(TimeVariable(1.0)))
+    @test ismissing(_vectorfield(AlgebraicVariable(x)))
+    @test ismissing(_vectorfield(VectorfieldVariable(StateVariable(x))))
+
+    @test _vectorfield(StateVariable(x)) == VectorfieldVariable(zero(x))
+    @test _vectorfield(StateWithError(StateVariable(x))) == VectorfieldVariable(zero(x))
+
+end
+
+
+@testset "$(rpad("State Constructor and Access Functions",80))" begin
+
+    data = (
+        t=TimeVariable(0.0),
+        q=StateVariable(rand(3)),
+        p=StateVariable(rand(3)),
+        λ=AlgebraicVariable(rand(2)),
+    )
+
+    st = State(data)
+
+    @test state(st) == st.state
+    @test solution(st) == st.solution
+    @test vectorfield(st) == st.vectorfield
+
+    @test keys(st) == keys(state(st))
+
+    @test st.t == data.t
+    @test st.q == data.q
+    @test st.p == data.p
+    @test st.λ == data.λ
+
+    @test hasproperty(st, :t)
+    @test hasproperty(st, :q)
+    @test hasproperty(st, :p)
+    @test hasproperty(st, :λ)
+    @test hasproperty(st, :q̇)
+    @test hasproperty(st, :ṗ)
+
+    @test :t ∈ keys(st)
+    @test :q ∈ keys(st)
+    @test :p ∈ keys(st)
+    @test :λ ∈ keys(st)
+    @test :q̇ ∈ keys(st)
+    @test :ṗ ∈ keys(st)
+
+    @test :t ∈ keys(state(st))
+    @test :q ∈ keys(state(st))
+    @test :p ∈ keys(state(st))
+    @test :λ ∈ keys(state(st))
+    @test :q̇ ∈ keys(state(st))
+    @test :ṗ ∈ keys(state(st))
+
+    @test :t ∈ keys(solution(st))
+    @test :q ∈ keys(solution(st))
+    @test :p ∈ keys(solution(st))
+    @test :λ ∈ keys(solution(st))
+
+    @test :t ∉ keys(vectorfield(st))
+    @test :q ∈ keys(vectorfield(st))
+    @test :p ∈ keys(vectorfield(st))
+    @test :λ ∉ keys(vectorfield(st))
+
+end