Abstract: A specimen holder assembly (500) suitable for tomographic inspection of a specimen in a transmission electron microscope comprising: a body portion (501) in the form of an elongate member arranged to be removably insertable into the column of the microscope; and a manipulator portion having a first axis, the manipulator portion comprising: a specimen mount portion (510) configured to support the specimen; a specimen translation assembly operable to translate the specimen mount portion with respect to the body portion; and a specimen rotation assembly (540) coupled to the body portion and to the specimen translation assembly (530), the specimen rotation assembly being operable to rotate the specimen translation assembly relative to the body portion about the first axis.