Nouns are the most important and highly used words in all the languages and Nominalisation is the most complex but interesting part of the same. This book explores different aspects of the Nouns- their formations, their classifications, their affinities and differences with other parts of speech, their forms and functions as well as modifications, determinations, coordinations, appositions etc. in phrase and clause structure and their substitutions i.e. Pronominalisations and Nominalizations in Assamese language. Assamese is a New Indo Aryan Language under Satam group of Indo-European family, spoken in Assam and in its surrounding states of N E India. Besides above mentioned aspects of Assamese, this book consists of an Introduction comprising a short description of the language and a discussion on the grammatical units of it.