diff --git a/Taskfile.yml b/Taskfile.yml
index b327b76..bafff43 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -64,7 +64,7 @@ tasks:
     cmds:
       - go test ./collections
 
-  tt:
+  tn:
     cmds:
       - go test
 
diff --git a/file-systems.go b/file-systems.go
index 5ed0c55..e7e7947 100644
--- a/file-systems.go
+++ b/file-systems.go
@@ -5,6 +5,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"strings"
 )
 
 // 🔥 An important note about using standard golang file systems (io.fs/fs.FS)
@@ -254,6 +255,48 @@ func (f *makeDirAllFS) MakeDirAll(name string, perm os.FileMode) error {
 	return os.MkdirAll(path, perm)
 }
 
+// EnsurePathAt ensures that the specified path exists (including any non
+// existing intermediate directories). Given a path and a default filename,
+// the specified path is created in the following manner:
+// - If the path denotes a file (path does not end is a directory separator), then
+// the parent folder is created if it doesn't exist on the file-system provided.
+// - If the path denotes a directory, then that directory is created.
+//
+// The returned string represents the file, so if the path specified was a
+// directory path, then the defaultFilename provided is joined to the path
+// and returned, otherwise the original path is returned un-modified.
+// Note: filepath.Join does not preserve a trailing separator, therefore to make sure
+// a path is interpreted as a directory and not a file, then the separator has
+// to be appended manually onto the end of the path.
+func (f *makeDirAllFS) Ensure(as PathAs,
+) (at string, err error) {
+	if !fs.ValidPath(as.Name) {
+		return "", NewInvalidPathError(as.Name)
+	}
+
+	var (
+		file string
+	)
+
+	if f.FileExists(as.Name) {
+		_, file = filepath.Split(as.Name)
+
+		return file, nil
+	}
+
+	if f.DirectoryExists(as.Name) {
+		return as.Default, nil
+	}
+
+	if as.AsFile {
+		directory, file := SplitParent(as.Name)
+
+		return file, f.MakeDirAll(directory, as.Perm)
+	}
+
+	return as.Default, f.MakeDirAll(as.Name, as.Perm)
+}
+
 // 🎯 removeFS
 
 type removeFS struct {
@@ -501,3 +544,7 @@ func compose(root string) *entities {
 		reader: reader,
 	}
 }
+
+func join(segments ...string) string {
+	return strings.Join(segments, "/")
+}
diff --git a/fs-ensure-at_test.go b/fs-ensure-at_test.go
new file mode 100644
index 0000000..a1fe04e
--- /dev/null
+++ b/fs-ensure-at_test.go
@@ -0,0 +1,207 @@
+package nef_test
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing/fstest"
+
+	. "github.com/onsi/ginkgo/v2" //nolint:revive // ok
+	. "github.com/onsi/gomega"    //nolint:revive // ok
+
+	nef "github.com/snivilised/nefilim"
+	lab "github.com/snivilised/nefilim/internal/laboratory"
+)
+
+var _ = Describe("Ensure", Ordered, func() {
+	var (
+		mocks *nef.ResolveMocks
+		mapFS *makeDirMapFS
+		root  string
+		fS    nef.MakeDirFS
+	)
+
+	BeforeAll(func() {
+		root = Repo("test")
+	})
+
+	BeforeEach(func() {
+		mocks = &nef.ResolveMocks{
+			HomeFunc: func() (string, error) {
+				return filepath.Join(string(filepath.Separator), "home", "prodigy"), nil
+			},
+			AbsFunc: func(_ string) (string, error) { // no-op
+				return "", errors.New("not required for these tests")
+			},
+		}
+
+		mapFS = &makeDirMapFS{
+			mapFS: fstest.MapFS{
+				filepath.Join("home", "prodigy"): &fstest.MapFile{
+					Mode: os.ModeDir,
+				},
+			},
+		}
+		scratch(root)
+
+		fS = nef.NewMakeDirFS(nef.At{
+			Root: root,
+		})
+	})
+
+	DescribeTable("local-fs",
+		func(entry fsTE[nef.MakeDirFS]) {
+			if entry.arrange != nil {
+				entry.arrange(entry, fS)
+			}
+			entry.action(entry, fS)
+		},
+		func(entry fsTE[nef.MakeDirFS]) string {
+			return fmt.Sprintf("🧪 ===> given: '%v', %v should: '%v'",
+				entry.given, entry.op, entry.should,
+			)
+		},
+
+		Entry(nil, fsTE[nef.MakeDirFS]{
+			given:   "path exists as file",
+			should:  "return filename of path",
+			op:      "Ensure",
+			require: lab.Static.FS.Scratch,
+			target:  lab.Static.FS.Ensure.Log.File,
+			arrange: func(entry fsTE[nef.MakeDirFS], _ nef.MakeDirFS) {
+				directory := lab.Static.FS.Ensure.Default.Directory
+				Expect(require(root, directory, entry.target)).To(Succeed())
+			},
+			action: func(entry fsTE[nef.MakeDirFS], fS nef.MakeDirFS) {
+				result, err := fS.Ensure(
+					nef.PathAs{
+						Name:    entry.target,
+						Default: lab.Static.FS.Ensure.Default.File,
+						Perm:    lab.Perms.Dir,
+					},
+				)
+				Expect(err).To(Succeed())
+				_, file := filepath.Split(lab.Static.FS.Ensure.Log.File)
+				Expect(result).To(Equal(file))
+			},
+		}),
+
+		Entry(nil, fsTE[nef.MakeDirFS]{
+			given:   "path exists as directory",
+			should:  "return default",
+			op:      "Ensure",
+			require: lab.Static.FS.Scratch,
+			target:  lab.Static.FS.Ensure.Log.Directory,
+			arrange: func(entry fsTE[nef.MakeDirFS], _ nef.MakeDirFS) {
+				Expect(require(root, entry.target)).To(Succeed())
+			},
+			action: func(entry fsTE[nef.MakeDirFS], fS nef.MakeDirFS) {
+				_, file := filepath.Split(lab.Static.FS.Ensure.Default.File)
+				result, err := fS.Ensure(
+					nef.PathAs{
+						Name:    entry.target,
+						Default: file,
+						Perm:    lab.Perms.Dir,
+					},
+				)
+				Expect(err).To(Succeed())
+				Expect(result).To(Equal(file))
+			},
+		}),
+
+		Entry(nil, fsTE[nef.MakeDirFS]{
+			given:   "file does not exist",
+			should:  "create parent directory and return file",
+			op:      "Ensure",
+			require: lab.Static.FS.Scratch,
+			target:  lab.Static.FS.Ensure.Log.File,
+			from:    lab.Static.FS.Ensure.Home,
+			arrange: func(entry fsTE[nef.MakeDirFS], _ nef.MakeDirFS) {
+				parent := Join(entry.require, entry.from)
+				Expect(require(root, parent)).To(Succeed())
+			},
+			action: func(entry fsTE[nef.MakeDirFS], fS nef.MakeDirFS) {
+				_, file := filepath.Split(lab.Static.FS.Ensure.Default.File)
+				result, err := fS.Ensure(
+					nef.PathAs{
+						Name:    entry.target,
+						Default: file,
+						Perm:    lab.Perms.Dir,
+						AsFile:  true,
+					},
+				)
+				Expect(err).To(Succeed())
+				ensureAt := lab.Static.FS.Ensure.Default.Directory
+				Expect(AsDirectory(ensureAt)).To(ExistInFS(fS))
+				_, file = filepath.Split(entry.target)
+				Expect(result).To(Equal(file))
+			},
+		}),
+
+		Entry(nil, fsTE[nef.MakeDirFS]{
+			given:   "directory does not exist",
+			should:  "create directory and return default",
+			op:      "Ensure",
+			require: lab.Static.FS.Scratch,
+			target:  lab.Static.FS.Ensure.Log.Directory,
+			from:    lab.Static.FS.Ensure.Home,
+			arrange: func(entry fsTE[nef.MakeDirFS], _ nef.MakeDirFS) {
+				parent := Join(entry.require, entry.from)
+				Expect(require(root, parent)).To(Succeed())
+			},
+			action: func(entry fsTE[nef.MakeDirFS], fS nef.MakeDirFS) {
+				_, file := filepath.Split(lab.Static.FS.Ensure.Default.File)
+				result, err := fS.Ensure(
+					nef.PathAs{
+						Name:    entry.target,
+						Default: file,
+						Perm:    lab.Perms.Dir,
+					},
+				)
+				Expect(err).To(Succeed())
+				ensureAt := lab.Static.FS.Ensure.Default.Directory
+				Expect(AsDirectory(ensureAt)).To(ExistInFS(fS))
+				Expect(result).To(Equal(file))
+			},
+		}),
+	)
+
+	DescribeTable("with mapFS",
+		func(entry *ensureTE) {
+			home, _ := mocks.HomeFunc()
+			location := TrimRoot(filepath.Join(home, entry.relative))
+
+			if entry.directory {
+				location += string(filepath.Separator)
+			}
+
+			actual, err := nef.EnsurePathAt(location, lab.Static.FS.Ensure.Default.File, lab.Perms.File, mapFS)
+			directory, _ := filepath.Split(actual)
+			directory = filepath.Clean(directory)
+			expected := TrimRoot(Path(home, entry.expected))
+
+			Expect(err).Error().To(BeNil())
+			Expect(actual).To(Equal(expected))
+			Expect(AsDirectory(TrimRoot(directory))).To(ExistInFS(mapFS))
+		},
+		func(entry *ensureTE) string {
+			return fmt.Sprintf("🧪 ===> given: '%v', should: '%v'", entry.given, entry.should)
+		},
+
+		XEntry(nil, &ensureTE{
+			given:    "path is file",
+			should:   "create parent directory and return specified file path",
+			relative: filepath.Join("logs", "test.log"), // home/logs/test.log
+			expected: "logs/test.log",
+		}),
+
+		XEntry(nil, &ensureTE{
+			given:     "path is directory",
+			should:    "create parent directory and return default file path",
+			relative:  "logs/",
+			directory: true,
+			expected:  "logs/default-test.log",
+		}),
+	)
+})
diff --git a/internal/laboratory/static.go b/internal/laboratory/static.go
index 83f1c5b..db6befc 100644
--- a/internal/laboratory/static.go
+++ b/internal/laboratory/static.go
@@ -12,6 +12,12 @@ type (
 		Destination string
 	}
 
+	Ensure struct {
+		Home    string
+		Default Pair
+		Log     Pair
+	}
+
 	Pair struct {
 		File      string
 		Directory string
@@ -45,6 +51,7 @@ type (
 	StaticFs struct {
 		Copy     Copy
 		Create   Create
+		Ensure   Ensure
 		Existing Pair
 		MakeDir  MakeDir
 		Move     Move
@@ -78,6 +85,17 @@ var (
 			Create: Create{
 				Destination: "scratch/pictures-of-you.CREATE.txt",
 			},
+			Ensure: Ensure{
+				Home: "home/marina",
+				Default: Pair{
+					File:      "scratch/home/marina/logs/default-test.log",
+					Directory: "scratch/home/marina/logs",
+				},
+				Log: Pair{
+					File:      "scratch/home/marina/logs/test.log",
+					Directory: "scratch/home/marina/logs",
+				},
+			},
 			Existing: Pair{
 				File:      "data/fS/paradise-lost.txt",
 				Directory: "data/fS",
diff --git a/make-dir-map-fs_test.go b/make-dir-map-fs_test.go
index 76edb3e..07db3c8 100644
--- a/make-dir-map-fs_test.go
+++ b/make-dir-map-fs_test.go
@@ -6,6 +6,8 @@ import (
 	"path/filepath"
 	"strings"
 	"testing/fstest"
+
+	nef "github.com/snivilised/nefilim"
 )
 
 type (
@@ -74,3 +76,9 @@ func (f *makeDirMapFS) MakeDirAll(path string, perm os.FileMode) error {
 
 	return nil
 }
+
+func (f *makeDirMapFS) Ensure(as nef.PathAs,
+) (at string, err error) {
+	_ = as
+	panic("NOT-IMPL: makeDirMapFS.Ensure")
+}
diff --git a/nefilim-defs.go b/nefilim-defs.go
index 2c92ad3..97a42ab 100644
--- a/nefilim-defs.go
+++ b/nefilim-defs.go
@@ -49,11 +49,31 @@ type (
 		ReadFileFS
 	}
 
+	// PathAs used with Ensure to define how to ensure that a path exists
+	// at the location specified
+	PathAs struct {
+		Name    string
+		Default string
+		Perm    os.FileMode
+		AsFile  bool
+	}
+
 	// MakeDirFS is a file system with a MkDirAll method.
 	MakeDirFS interface {
 		ExistsInFS
 		MakeDir(name string, perm os.FileMode) error
 		MakeDirAll(name string, perm os.FileMode) error
+		// Ensure makes sure that a path exists (PathAs.Name). If the path exists
+		// as a file then no directories need to be created and this file name
+		// (PathAs.Name) is returned. If the path exists as a directory, then again
+		// no directories are created, but the default (PathAs.Default) is returned.
+		//
+		// If the path does not exist, then 1 of 2 things can happen. If PathAs.AsFile
+		// is set to true, then the parent of the path is created, and file portion
+		// of the path is returned. When PathAs.AsFile is not set, ie the path
+		// provided is to be interpreted as a directory, then this directory is
+		// created and the default is returned.
+		Ensure(as PathAs) (string, error)
 	}
 
 	// MoveFS
diff --git a/nefilim-suite_test.go b/nefilim-suite_test.go
index 66fd1b3..4069518 100644
--- a/nefilim-suite_test.go
+++ b/nefilim-suite_test.go
@@ -143,6 +143,10 @@ func Repo(relative string) string {
 	return Path(repo, relative)
 }
 
+func Join(segments ...string) string {
+	return strings.Join(segments, "/")
+}
+
 func Normalise(p string) string {
 	return strings.ReplaceAll(p, "/", string(filepath.Separator))
 }