Complex sentence: Inspired by the Utopian novel "Looking Backward" and Henry George's work "Progress and Poverty", Howard published his book "Garden Cities of To-morrow" in 1898, commonly regarded as the most important book in the history of urban planning.
Split into simpler sentences: Inspired by the Utopian novel "Looking Backward" and Henry George's work "Progress and Poverty", Howard published his book "Garden Cities of To-morrow" in 1898. His work is commonly regarded as the most important book in the history of urban planning.