There are many books on witnessing today, most of which are just a collection of prepared anwers to the most common objections of cultists, atheists and members of other religions. This approach may be good to sell books, but not to win souls, because it does not take count that every individual is different, and we have to adapt in order to be effective evangelizers.
Spurgeon's approach is completely different. He does not give us a systematic approach to witnessing, but rather he simply explains what it means to win a soul, why it is so important, possible obstacles and so forth with so much heart, dedication and evident love for God's Word that after I finished it I was totally inspired to go out on the streets and tell everybody about the wonderful Good News of Jesus Christ.
Every page is filled with personal stories, anecdotes and practical examples that make this book a pleasure to read.
A must read.