The principles of product development flow

is an excellent book by Donald Reinersten (isbn 978-1-935401-00-1). As usual I'm going to quote from a few pages:
Operating a product development process near full utilisation is an economic disaster.
When we emphasise flow, we focus on queues rather than timelines.
Almost any specialist can become a queue.
We grow queues much faster than we can shrink them.
When queues are large, it is very hard to create urgency.
Queues amplify variability. Moving from 75 to 95% utilisation increases variability by 25 times.
Sequential phase-gate processes have inherently large batch transfers.
Large batches encourage even larger batches.
Reducing batch size is usually the single most effective way to reduce queues.
Companies inevitably feel they can computerise this whiteboard, however, they almost always create a more elegant but less useful system.
The speed of feedback is at least two orders of magnitude more important to product developers than manufacturers.
The human effect of fast feedback loops are regenerative. Fast feedback gives people a sense of control; they use it, see results, and this further reinforces their sense of control.
Homeostasis is the tendency of a system to maintain its current state.
In product development, our problem is virtually never motionless engineers. It is almost always motionless work products.
Opportunities get smaller with time, and obstacles get larger.
The scarcest resource is always time.
To align behaviours reward people for the work of others.
It has been said that one barbarian could defeat one Roman soldier in combat, but that 1,000 Roman soldiers could always defeat 1,000 barbarians.
The Marines, and all other elite organisations, maintain continuity in their organisational units.