A heat exchanger comprising: a core configured to receive and place a plurality of mediums (20,22) in at least one heat exchange relationship; and a first manifold (14A,114) connected to and in fluid communication with the core at a first manifold/core interface, the first manifold comprising: a first end (26A,126) distal from the core with at least one port adapted to receive or discharge a first medium of the plurality of mediums; a second end (28A,128) joined to the core at the first manifold/core interface adapted to transfer the first medium to or from a plurality of first heat exchange passages in the core; a plurality of first guide vanes defining a plurality of individual layers for the first medium; and a plurality of second guide vanes dividing each of the plurality of individual layers into a plurality of first discrete manifold flow passages extending at least part of a distance from the first end to the second end of the first manifold; wherein each of the plurality of individual layers is formed as gradual transitions from the first end (26A,126) to the second end (28A, 128) and comprises two adjacent first guide vanes and comprises second guide vanes therein; characterised in that each of the plurality of individual layers are cantilevered from the first end of the first manifold; and each of the plurality of individual layers are unsupported at the second end of the first manifold, thereby allowing elastic deformity of each individual layer relative to an adjacent individual layer. a core configured to receive and place a plurality of mediums (20,22) in at least one heat exchange relationship; and a first manifold (14A,114) connected to and in fluid communication with the core at a first manifold/core interface, the first manifold comprising: a first end (26A,126) distal from the core with at least one port adapted to receive or discharge a first medium of the plurality of mediums; a second end (28A,128) joined to the core at the first manifold/core interface adapted to transfer the first medium to or from a plurality of first heat exchange passages in the core; a plurality of first guide vanes defining a plurality of individual layers for the first medium; and a plurality of second guide vanes dividing each of the plurality of individual layers into a plurality of first discrete manifold flow passages extending at least part of a distance from the first end to the second end of the first manifold; wherein each of the plurality of individual layers is formed as gradual transitions from the first end (26A,126) to the second end (28A, 128) and comprises two adjacent first guide vanes and comprises second guide vanes therein; characterised in that each of the plurality of individual layers are cantilevered from the first end of the first manifold; and each of the plurality of individual layers are unsupported at the second end of the first manifold, thereby allowing elastic deformity of each individual layer relative to an adjacent individual layer. a first end (26A,126) distal from the core with at least one port adapted to receive or discharge a first medium of the plurality of mediums; a second end (28A,128) joined to the core at the first manifold/core interface adapted to transfer the first medium to or from a plurality of first heat exchange passages in the core; a plurality of first guide vanes defining a plurality of individual layers for the first medium; and a plurality of second guide vanes dividing each of the plurality of individual layers into a plurality of first discrete manifold flow passages extending at least part of a distance from the first end to the second end of the first manifold; wherein each of the plurality of individual layers is formed as gradual transitions from the first end (26A,126) to the second end (28A, 128) and comprises two adjacent first guide vanes and comprises second guide vanes therein; characterised in that each of the plurality of individual layers are cantilevered from the first end of the first manifold; and each of the plurality of individual layers are unsupported at the second end of the first manifold, thereby allowing elastic deformity of each individual layer relative to an adjacent individual layer.