The book is devoted to the thermal stability of Polyalkanimids - thermoplastic heat-resistant polymers . Composite materials based on PAI are recommended for the manufacture of electrical and structural parts , replacement of reactoplastics in particularly critical parts (operating in a wide temperature range of 150-200 C , experiencing short-term temperature loads up to 250-270 C , in a closed volume, vacuum up to 10 mm Hg. st. and others. ). Unique injection molding properties of PAI-based composite materials allow to manufacture parts of complex configuration, including, reinforced and non-reinforced. The book discusses in detail the features of destruction and stabilization of not only PAI and composite materials based on it. but also other heat-resistant heterochain polymers, presents modern ideas about the mechanism of destructive transformations in a wide temperature range from the processing temperatures to the operating temperatures of the material in the products. Stabilization issues are considered. Particular attention is paid to PAI-based mixtures and alloys, as well as the recycling of these materials. The book is designed for materials scientists, technologists, designers and researchers who develop and use heat-resistant and special polymers and polymer materials.