Islam and the prayers

I bought a book recently called 'menjamak shalat tanpa halangan, boleh atau tidak' (Combining the prayers without any reason, can or cannot). The writer put in all the prophets saying(hadith) as found in sahih Bukhari, sahih Muslim and others on this subject for us to read. He also writes about the discussion among well known Islamic scholars such as Imam Shafie, Imam Malik and others on this subject.
The conclusion. Yes! We CAN.
I have been reading about this subject for a long time already and always believed that we indeed CAN. In fact, I have been practicing it every now and then. This book reinforced my believe.