The changes started in education during the last decades are not possible to be introduced without involving all education institution staff, and it is the involvement where staff members not only work but also mutually cooperate and totally understand the necessity of this cooperation for the achievement of school goals. The research done in Liep?ja city comprehensive schools and the research in comprehensive schools of Latvia gives information about comprehensive school leadership and their staff’s attitude to teamwork, school culture, their readiness and desire and opportunity to cooperate in school improvement and development. The research reveals teamwork principles in school staff participation in school management, mutual coherences of school culture and pupils’ study achievements, as well as their mutual connections with the school type. It is also essential to point out that such research in the sector of comprehensive schools of Latvia has not so far been done. The book is meant for everyone connected with the educational field whose topic of interest is teamwork and who would like to get acquainted with a unique research which so far has not been done in Latvia.