The book "Thoughts on the Necessity of Improving the Condition of the Slaves in the British Colonies with a View to their Final Emancipation; on the Possibility, Safety, and Advantages of the Last Measure" was written by the prominent English abolitionist Thomas Clarkson. In his work, the author examines the problem of slavery in the British colonies, making arguments in favor of improving the living conditions of slaves and their subsequent liberation. Clarkson expresses his conviction that slavery is a social disadvantage that requires further efforts to be fully eliminated. He argues for the feasibility of this goal and emphasizes the safety and many benefits of freeing the slaves. The author draws attention to the humanitarian aspect of the problem and the importance of ensuring basic rights for all people, regardless of their status. Thomas Clarkson's book became an important contribution to the struggle for the liberation of slaves and recognition of their rights. The author offers constructive approaches to solving the problem of slavery and supports the idea of changes in legislation and society to achieve absolute liberation.