I just bought The New Testament in Antiquity which was pricey. It’s a good introduction to the New Testament since it focuses much on the historical background which is why I bought it. I’m planning to buy Beginning from Jerusalem by James Dunn which is massive. I got the first volume. It’s pricey but after reading a review here it looks set for my bookshelf. The only problem is money as it costs a heafty RM 200++ bucks!