Plastic surgery of the middle ear has gained tremendous ground for otology, especially through the outstanding work of the German Professors Wullstein and Zöllner. A patient with a chronic middle ear inflammation, frequently with greatly impaired hearing, may now be relieved of his infection and the false tumours (so-called cholesteatomas) that often accompany these forms of ear inflammation as well as having his hearing improved to a certain extent. Thanks to the advances made by these eminent workers in otologic surgery this has become possible not only as earlier through radical operations on the cell system of the ear but also now through plastic operations on the elements of the middle ear, the mucosa, the auditory ossicles and the tympanum, and in many cases with astonishing improvement to the hearing. Indeed, the results are sometimes so good that patients, who before such an operation were auditory invalids, recover almost normal hearing. One is almost inclined to say that this form of surgery represents, if possible, an even greater advance for otology than the otosclerosis operations. Professor Frenckner has discussed in this number of Acta Oto-Laryngologica the general problems about tympanoplasty surgery and has given an account of his experience from six years' work in this branch of surgery. The operation was done in 39 cases, and about half of the patients have been followed up for as long as 1 1/2 years after operation. Audiograms were taken during the period of healing and the results have been classified in the following groups. Group I 37 cases followed for from 1 to 4 months after operation. Group II 33 cases followed for from 5 to 9 months after operation. Group III 17 cases followed for from 12 to 18 months after operation. The patients undergoing operation as a rule had extremely pronounced impairment of hearing, and the mean decibel level for 500, 1000 and 2000 cycles per second was as high as 55 db in the cases examined before operation. The cases in question were those of patients with clean radical operative cavities and impaired hearing, with discharging radically operated ears and impaired hearing, with chronic purulent otitis and marginal perforations with and without cholesteatoma, and patients with central perforations in chronic otitis with dry or suppurating ears. In addition a number of cases of adhesive otitis with severely collapsed, scarred ear drums and chronic mastoiditis were included. The results of the operations with respect to the hearing are shown in the Table 8, page 316.