The aim of this doctoral thesis was the development and implementation of new methods for micro- and nano-characterisation in natural fibre science. The main experimental devices for this were nanoindenter and atomic force microscope. A new method for measuring the cell wall-adhesive interaction directly at the interface by means of nanoindentation is presented in Paper 1. This method is applied in Paper 2 to analyse dfferences in the bonding behaviour of two types of adhesives to the S2 and S3 cell wall, respectively, of spruce wood. Measuring nanoscale roughness with the AFM, Paper 3 investigates the influence of roughness on the optical appearance of ligno-cellulosic fibres. Paper 4 examines temporal changes in surface chemistry of the S2- and S3 cell wall layer by applying a mechanical mapping mode. Paper 5 introduces scanning thermal microscopy to evaluate the direction-dependent thermal conductivity of wood samples on the cell wall level. Further work on this method with the aim of obtaining quantitative results for fibrous materials is presented in the experimental section of this thesis.