The club have two main types of assets. These are 'tangible assets' and 'intangible assets'. Tangible assets are bricks and mortar and land. Intangible assets are the value of the players that have been bought in to the club.
Both sorts of assets lose value over their lifetime, the players value reduced steadily over the life of their contract, this is explained more fully in the Amortisation section.
The first graph below shows the value of the tangible assets. It is clear there is little change in these. It would take the building of a new ground, or training facilities for these to change dramatically.
The second graph shows the intangible assets or the remaining book value of the bought players. It is clear that there is a huge leap in the value of the players on the books. This can be a good sign of a club growing, although it is not clear whether it is in Bolton's case. There is a big leap, but this has come from the club expensively borrowing huge amounts of money to finance it all.